1.1 Anorganische Spurenanalytik
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Eingeladener Vortrag
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Stable isotope ratios and trace element concentrations of fossil bones and teeth are important geochemical proxies for the reconstruction of diet and past environment in archaeology and palaeontology. However, since diagenesis can significantly alter in vivo incorporated isotope signatures and elemental compositions, it is important to understand alteration processes. Here, we present the results of in vitro alteration experiments of dental tissues from a modern African elephant molar in aqueous solutions at 30 °C and 90 °C for 4 to 63 days each. Dental cubes with ≈3 mm edge length, comprising both enamel and dentin, were placed into 2 ml of an acidic (HNO3) aqueous solution (pH ≈1) enriched with different isotopes (25Mg, 44Ca, 67Zn, 86Sr). Element and isotope distribution profiles across the different dental cubes were measured with LA-(MC-)ICP-MS and EMPA, while potential changes of the bioapatite crystal structure were characterised by Raman spectroscopy. Isotope ratios measured by LA-(MC-)ICP-MS revealed an alteration of the outer ≈200-300 μm of the enamel in all experiments. Dentin was fully altered after one week (at 90 °C) and the tracer solution started to penetrate through the dentin even into the innermost enamel. However, the central part of the enamel remained unaltered. The Raman spectra suggest a strong recrystallization in the dentin and in the outer ≈40 μm of the enamel and a partial demineralisation of the outer rim of the cubes. Our results indicate that independent of time, temperature or low initial pH, enamel apatite shows a high resistance against the experimental alteration in structure and isotopic composition, in contrast to dentin apatite.
In the interest of exploring their potential in the field of single particle analysis, a Microdroplet Generator (MDG) was coupled to an ICP-ToF-MS.
Isotopic Dilution Analysis was also incorporated for the size determination of three different Platinum Nanoparticles samples (50, 63 and 70 nm). The performance of the technique was validated by comparison to traditional size characterization techniques (sp-ICP-ToF-MS, TEM), while the robustness of the technique was proven by incorporating NaCl in the samples’ matrix, up to 100 mg/L.
The introduction of fluorine in organic molecules leads to new chemical/physical properties. Especially in the field of pharmaceuticals, fluorinated organic molecules are becoming more and more popular and at present amount up to 25% of market share, with an upward trend. The main benefits of fluorinated pharmaceuticals are: (i) enhanced fat solubility; (ii) enhanced interaction of catalytic-center of enzymes with fluorine-drugs; (iii) a delayed metabolism within the human body. Highly fluorinated organic substances are also used in technical applications (e.g. coatings, fire-extinguishing agents).
Due to the broad variety of fluorinated substances and increasing production volumes numerous and up to date unknown fluorine-species are most likely to be present in the (aquatic) environment. Analytical methods to assess the degree of contamination of surface waters with organically bound fluorine are highly needed and up to now only combustion ion chromatography based method is available, which is relatively laborious.
Since a few years’ high resolution-continuum source-graphite furnace atomic absorption spectrometers (HR-CS-GFAAS) are commercially available from Analytik Jena. By means of this technique, the detection of high resolution molecular absorption spectra (MAS) is enabled. Thus, fluoride is detectable upon the addition of a modifier and the formation of a diatomic molecule (e.g. GaF). Just recently, we applied this technique for total fluorine (mainly dissolved fluoride) analysis in river water samples.
In the present work a HR-CS-GFMAS method for extractable organically bound fluorine (EOF) analysis in surface water samples was developed by us. The method is based on SPE extraction of organically bound fluorine even in the presence of high fluoride concentrations followed by HR-CS-GFMAS analysis upon elution. Due to high enrichment factors, LODs in the low ng/L range were achieved. We successfully applied our SPE HR-CS-GFMAS method to Rhine water samples and EOF in the range of about 50-300 ng/L was detectable.
Isotope reference materials
(2022)
The variation of isotope ratios is increasingly used to unravel natural and technical questions. In the past, the investigation and interpretation of such variations was the field of a limited number of experts. With new upcoming techniques and research topics in the last decades, such as provenance or food authenticity studies, the number of published isotope data strongly increased. Instrumental developments such as the enhancement of inductively coupled plasma mass spectrometers (ICP-MS) from an instrument for simple quantitative analysis to highly sophisticated isotope ratio machines influenced this process significantly. While in former times only experts in mass spectrometry were able to produce reliable isotope data, nowadays many laboratories, never been in touch with mass spectrometry before, produce isotope data with an ICP-MS. Isotope reference materials (iCRM) are indispensable to enable a reliable method validation or in rare cases even SI-traceability. The fast development and the broad availability of ICP-MS also lead to an expansion of the classical research areas and new elements are under investigation. Irrespective of the investigated element or the knowledge of the user all isotope ratio applications require reference materials either for correction of instrumental isotope fractionation, for method validation or to provide a common accepted basis as needed for delta measurements. This presentation will outline the basic principles and illustrate the urgent need for new iCRMs. Consequently, the production and certification of iCRMs will be discussed and illustrated by examples of already completed certification projects. Finally, plans for future iCRMs to be produced at BAM will be presented.
This presentation provides a short introduction to the Commission on Isotopic Abundances and Atomic Weights (CIAAW). It describes the role of the Commission and provides an insight into its work and the corresponding principal tasks. Finally, it provides the reader with the latest achievements and with the most recent publications.
What isotopes can do...
(2019)
The reference method for obtaining absolute isotope ratios still is the isotope mixture approach. Due the huge efforts required the full isotope mixture approach is applied only by a few institutes worldwide. To enable an IRWG key comparison with a sufficiently large number of participants a proposal for absolute cu isotope ratios is presented where participants will be provided with the enriched isotopes, the isotope mixtures and the samples. In parallel a pilot study will be organized where alternative approaches for obtaining absolute Cu isotope ratios can be applied.
Pb isotope ratio analysis
(2023)
Sr isotope ratio analysis
(2023)
Detector deadtime
(2023)
Isotope Ratio Analysis
(2023)
The calibration of isotope ratio measurements is an ongoing challenge since instrumental isotope fractionation (IIF) has been detected in mass spectrometry (MS). There is a variety of approaches which either bypass IIF such as delta measurements or refer to reference materials (RMs) and thus shifting the problem of calibration to somebody else: the RM producer. For certifying isotope RMs with absolute isotope ratios only a few approaches are available, namely the isotope mixture approach, the double spike approach, the mass bias regression model and total evaporation in TIMS. All of them require either enriched isotopes, isotope RMs of another element or an RM for correcting residual error. As the enriched isotopes required for the isotope mixture and the double spike approach need to be fully characterized beforehand, all mentioned calibration approaches require a standard.
Here, a new and standard-free calibration approach for obtaining absolute isotope ratios of multi-isotopic elements has been developed. The underlying principle is that each MS suffers from IIF and thus yields a specific isotope fractionation line in a three-isotope diagram. When applying a second MS featuring a different ionization mechanism, we obtain a second isotope fractionation line with a different slope in the same three-isotope diagram. In both cases the absolute isotope ratios range somewhere on the isotope fractionation line. Consequentially, the intersect of both lines yield the absolute isotope ratios of the measured sample. This theory has been tested by measuring Cd and Pb isotope ratios of suitable isotope RMs with a TIMS and an ICP-MS, both equipped with multi-collector array. During the measurements the ionization conditions were changed such that different extent of the isotope fractionation has been achieved. With the resulting data set the theory described above could be verified. The obtained absolute isotope ratios were metrologically compatible with the certified isotope ratios. The remaining average bias of -5 ‰ can be reduced with further improvements. The calibration approach is universal and can be applied to any multi-isotopic element and it is not limited by the type of the mass spectrometer.
IRWG strategy update
(2023)
Multi-collector inductively coupled plasma-mass spectrometry (MC-ICP-MS) has evolved significantly since its introduction in 1992. The second and third generation instruments now allow isotope ratio measurements at unprecedented precisions, 0.001 % or better. However, precision alone is not enough for producing accurate and reliable isotope ratio measurements. Metrological considerations such as the selection of suitable calibration strategies, proper assessment of instrumental biases, and the estimation of overall measurement uncertainty remain critical to the measurement process. Properly assessed, measurement uncertainty then provides the interval within which a result can be considered both accurate and precise.
All mass spectrometric measurements are affected by instrumental mass discrimination and produce isotope ratios that are biased relative to their “true” ratio. To produce accurate and traceable isotope ratio measurements, it is imperative that certified isotope reference materials (iCRMs) be used for calibration and validation purposes. iCRMs reporting absolute isotope ratios are an analyst’s first choice, particularly when its uncertainty is sufficient for the intended use. However, when smaller uncertainties are required to resolve subtle differences between samples, delta-scale measurements become important. Here, the difference between an isotope ratio measured in a sample and in an internationally accepted isotope reference material (iRM) is determined. This deviation can be positive or negative relative to the iRM, is called a delta value, and is often expressed in per mil units.
This presentation will highlight the potential for MC-ICP-MS to produce isotope ratio measurements with minimal uncertainties by examining three applications involving Mg isotopes: 1) the certification of a set of iCRMs for their absolute isotope ratio using a gravimetric isotope mixture approach; 2) the comparison of these iCRMs with currently accepted Mg delta-scale reference materials through intercalibration, and 3) the determination of isotope fractionation exponents for geochemical applications.
An introduction into absolute isotope ratios is given, with application fields ranging from fundamental science to geochronology and forensics. This is followed by a proposal for developing new calibration approaches for obtaining absolute isotope ratios at unrivaled uncertainty levels. This new developments will set the basis for improvements in all scientific fields.
Technology critical elements (TCE) are key materials for high-tech products such as smartphones, notebooks and monitors. Their demand is expected to increase exponentially as a result of the shift towards greener economy through the deployment of renewable energy and electro mobility solutions (European Green Deal). This and the lack of natural resources in the EU, puts the market under pressure and leads to increasing prices. The need to secure TCE supply has become even more pressing under the current health crisis and it is a major objective of the Covid-19 Recovery Plan aimed at reinforcing Europe’s resilience and autonomy. A sustainable solution for solving this problem is first through recycling and finally through a circular economy. However, the analysis of waste streams is a complicating factor and requires suitable analytical solutions first, which need to be traceable to the SI to allow for comparability of measurement results throughout the recycling process or the circular economy. The required reference materials certified for TCE in the corresponding waste or secondary raw materials and specific documentary standards for TCE to comply with ISO/IEC 17025 requirements, however, are lacking. Furthermore, wastes from the urban mine are extremely heterogeneous, which makes the estimation of their TCE content difficult. Currently there is a lack of knowledge at the European level about the TCE stocks and flows in the urban mine. Given the high volume of waste generated and received, fast reliable analytical methods as well as sampling and sample preparation strategies are needed to determine the economic value of the waste and of the final product and to develop recycling procedures. Within this project we focus on a set of TCEs(Co, Ga, Ge, In, Ta, Nd, Pr, Dy, Gd, La, Au, Pt, Pd, Rh), which have been selected from the list of critical elements for Europe established by the EU in 2017. The overall objective of the project is to provide reliable and SI traceable determination of TCE in urban waste material at µg/g levels in order to increase the efficiency and accuracy of TCE recycling. This will be realized by developing validated SI-traceable reference methods, developing traceable and validated reference materials for the TCEs, validating the use of the routine methods and reference materials for real world applications and facilitating the take up of the technology and measurement infrastructure developed in the project by the measurement supply chain, standards developing organisations and end users.
The presentations gives a short introduction into isotope analysis illustrated by examples from archaeology, food provenancing and metrology. In the main part current projects on the provenance determination of cement, the intercalibration of Mg isotope reference materials and the development of a new calibration approach for isotope measurements are presented.
Absolute Isotope Ratios
(2018)
Measurement results and scientific models leading to important decisions in forensics, food fraud or climatology are based on isotope ratio data. Molar masses of multi-isotopic elements are as well based on isotope ratio data. Thus, in the case of Si, isotope ratios directly impact the redefinition of the SI base units kilogram and mole. Therefore, new strategies are required leading to new primary isotope reference materials, whose isotope ratios are traceable to the SI. This in turn will ensure the comparability of isotope ratio data and will render the traceability exception requested by the CCQM superfluous. Such new procedures will be developed for the key elements S, Si, Ca, Sr and Nd at relative uncertainty levels of ≤ 0.01 %.
This presentation gives a short overview of isotope ratio measurements being carried out in the past few years at BAM in different fields such as plant metabolism, food web structures and archaeology. The corresponding isotope reference materials which have been certified at BAM in parallel are presented as well. Additionally an outlook is being provided on future iRM projects.
Technologie-kritische Elemente (TCE) sind unentbehrliche Materialien für High-Tech Produkte wie Smartphones, Notebooks und Monitors. Ihr Bedarf wird voraussichtlich aufgrund des gesellschaftlichen Wandels hin zu einer grünen Ökonomie exponentiell ansteigen. Dieser Wandel wird vor allem auch durch erneuerbare Energien und Elektromobilität geprägt (European Green Deal). Diese Entwicklung in Verbindung mit einer nahezu fehlenden TCE Produktion in Europa setzt den Markt unter Druck und führt zu steigenden Preisen. Die Sicherung des TCE Nachschubs wurde in der gegenwärtigen Gesundheitskrise noch dringender und wurde daher auch zu einem der Hauptthemen des COVID-19 Recovery Plan, der eine Stärkung der europäischen Resilienz und Autonomie zum Ziel hat. Ein nachhaltige Lösung ist das Recycling der Abfall- bzw. Wertstoffe und letztendlich eine Circular Economy. Allerdings ist die Analyse von Abfallströmen schwierig und erfordert geeignete analytische Lösungen, die SI-rückführbare und somit vergleichbare Messergebnisse im gesamten Recyclingprozess ermöglichen. Die dafür erforderlichen, für TCE zertifizierte, Referenzmaterialien und nötige standardisierte Verfahren fehlen bisher nahezu vollständig. In diesem Beitrag werden die analytischen Herausforderungen, wie z.B. die extreme Heterogenität der Materialien, Schwierigkeiten beim Probenaufschluss und das Fehlen von Referenzmaterialien diskutiert. Und es wird das EMPIR-Projekt MetroCycleEU vorgestellt, dessen Ziel es ist Referenz- und Routineverfahren für ausgewählte TCE (Co, Ga, Ge, In, Ta, Nd, Pr, Dy, Gd, La, Au, Pt, Pd, Rh) zu entwickeln und Referenzmaterialien für Platinen, LEDs und Li-Batterien bereitzustellen.
IRWG strategy update
(2022)
Per- and polyfluoroalkyl substances (PFAS) are a large group of organofluorine surfactants used in the formulations of thousands of consumer goods. The continuous use of PFAS in household products and the discharge of PFAS from industrial plants into the sewer system have been resulted in contaminated effluents and sewage sludge from wastewater treatment plants (WWTPs) which became an important pathway for PFAS into the environment. Because sewage sludge is often used as fertilizer its application on agricultural soils has been observed as significant input path for PFAS into our food chain. To produce high-quality phosphorus fertilizers for a circular economy from sewage sludge, PFAS and other pollutants (e.g. pesticides and pharmaceuticals) must be separated from sewage sludge. Normally, PFAS are analyzed using PFAS protocols typically with time-consuming extraction steps and LC-MS/MS target quantification. However, for screening of PFAS contaminations in wastewater-based fertilizers also the DGT technique can be used for the PFAS extraction. Afterwards, combustion ion chromatography (CIC) can be applied to analyze the “total” amount of PFAS on the DGT binding layer. The DGT method was less sensitive and only comparable to the extractable organic fluorine (EOF) method values of the fertilizers in samples with >150 µg/kg, because of different diffusion properties for various PFAS, but also kinetic exchange limitations. However, the DGT approach has the advantage that almost no sample preparation is necessary. Moreover, the PFAS adsorption on the DGT binding layer was investigated via surface sensitive spectroscopical methods, such as Fourier-transform infrared (FT-IR) and fluorine K-edge X-ray absorption near-edge structure (XANES) spectroscopy.
Per- and polyfluoroalkyl substances (PFAS) are chemicals which were developed to improve humanity’s quality of life. Due to their high chemical stability and resistance to degradation by heat or acids, PFAS were used in a variety of consumer products. The continuous use of PFAS in household products and the discharge of PFAS from industrial plants into the sewer system resulted in the contamination of effluents and sewage sludge from wastewater treatment plants (WWTPs) (Roesch et al. 2022). Since sewage sludge is often used as fertilizer, its application on agricultural soils has been observed as a significant entry path for PFAS into the environment, specifically in our food chain. In Germany the sewage sludge/biosolid application on agricultural land was banned with the amendment of the German Sewage Sludge Ordinance and by 2029 sewage sludge application will be totally prohibited. However, phosphorus (P) from sewage sludge should still be recycled in WWTPs of cities with a population larger than 50,000 residents. To produce high-quality P-fertilizers for a circular economy, PFAS and other pollutants (e.g. pesticides and pharmaceuticals) must be separated from sewage sludge. Due to the strong diversity of industrial PFAS usage it is not clear if a safe application of novel recycled P-fertilizers from WWTPs can be guaranteed. Therefore, we analyzed various sewage sludges and wastewater-based fertilizers. Sewage sludge (SL) samples from various WWTPs in Germany and Switzerland, six sewage sludge ashes (SSA) from Germany, six thermally treated SL and SSA samples with different additives (temperatures: 700-1050 °C), two pyrolyzed SL samples (temperature: 400 °C) and two struvite samples from Germany and Canada were analyzed. The goal was to quantify PFAS in sewage sludges and wastewater-based P-fertilizers with the sum parameter extractable organic fluorine (EOF) by combustion ion chromatography (CIC). The results were compared with data from classical LC-MS/MS target analysis as well as selected samples by HR-MS suspect screening. The EOF values of the SLs mainly range between 154 and 538 µg/kg except for one SL which showed an elevated EOF value of 7209 µg/kg due to high organofluorine contamination. For the SSA samples the EOF values were lower and values between LOQ (approx. 60 µg/kg) and 121 µg/kg could be detected. For the pyrolyzed SLs no EOF values above the LOQ were detected. Moreover, the two wastewater-based struvite fertilizers contain 96 and 112 µg/kg EOF, respectively. In contrast to the EOF values, the sum of PFAS target values were relatively low for all SLs. Additional applied PFAS HR-MS suspect screening aimed to tentatively identify PFAS that could contribute to the hitherto unknown part of the EOF value. The majority of the detected fluorinated compounds are legacy PFAS such as short- and long-chain perfluorocarboxylic acids (PFCA), perfluorosulfonic acids (PFSA), polyfluoroalkyl phosphate esters (PAPs) and perfluorophosphonic acids (PFPA). Moreover, fluorinated pesticides, pharmaceutical as well as aromatic compounds were also identified, which are all included in the EOF parameter. Our research revealed that the current PFAS limit of 100 µg/kg for the sum of PFOS + PFOA in the German Fertilizer Ordinance is no longer up to date. Since the number of known PFAS already exceeds 10,000, the ordinance limit should be updated accordingly. Recent regulations and restrictions on using long-chain PFAS (≥C8) have resulted in a significant shift in the industry towards (ultra-)short-chain alternatives, and other, partly unknown, emerging PFAS. Ultimately, also fluorinated pesticides and pharmaceuticals, which end up as ultrashort PFAS in the WWTPs, have to be considered as possible pollutants in fertilizers from wastewater, too.
Laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) is increasingly used to study the distribution of metal-containing drugs, imaging probes and nanomaterials in connection with disease related changes and therapy progress. Additionally, biomolecules can be detected indirectly by using metal-tagged antibodies.
The extracellular matrix (ECM) is, besides the cells, an important component of all body tissues. The macromolecular network of the ECM consists of structural proteins (e.g., collagen, elastin) and proteoglycans composed of highly negatively charged carbohydrates, the glycosaminoglycans (GAGs), which are covalently linked to a protein core. Many diseases, including inflammatory processes and tumors, are associated with characteristic ECM changes at an early stage. Recent studies have shown that contrast agents for magnetic resonance imaging (MRI), which are based on gadolinium containing chelate complexes or iron oxide nanoparticles, can bind themselves to ECM components.
To elucidate the role of GAGs like keratan sulfate (KS) and its modification state in disease, highly specific tools are necessary. As a complement to conventional immunohistochemistry LA-ICP-MS was applied to investigate the distribution of KS in tissue thin sections using a well characterized anti-KS antibody labelled with metal ions. Furthermore, LA-ICP-MS was used for the detection of MRI contrast agents and the identification of their target cells and molecules in tissue samples from animal models, e.g. for cardiovascular diseases. The results show the possibilities of LA-ICP-MS for the elucidation of pathological tissue changes.
The interaction of nanoparticles (NPs) with cells has become a major field of interest, ranging from medical applications to nanotoxicology. Size, shape and surface modification of the NPs determine the uptake rate and pathway into the cells, and therefore impact specific cell components and processes.
Laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) is an established quantitative multi-elemental analysis and mapping technique. In recent years, it was shown that LA-ICP-MS can provide quantitative as well as distribution information of NPs in cell samples.
Here LA-ICP-MS was applied for the imaging of individual cells to study the uptake and intracellular processing of metal-containing nanostructures. Additionally, the local distribution of naturally occurring elements in cells like P was measured to indicate cell morphology. The cells were incubated with different types of NPs under varying experimental conditions. For LA analysis, the cells were fixed and dried.
Our findings show, that LA-ICP-MS is suitable for the localisation of nanoparticle aggregates within cellular compartments. The studied NPs accumulate in the perinuclear region in the course of intracellular processing, but do not enter the cell nucleus. The uptake efficiency depends strongly on the physicochemical properties of the nanostructures as well as on the incubation conditions like concentration and incubation time.
The results demonstrate the potential of LA-ICP-MS providing insight into NP uptake, intracellular distribution and cell-to-cell variation dependent on experimental parameters.
Nanoparticles (NPs) have found a wide range of applications in research and industry. Thereby the interaction of NPs with biological systems like cells has become a major field of interest, ranging from medical applications to nanotoxicology. Size, shape and surface modification of the nanomaterials determine the uptake rate and pathway into the cells, and therefore impact specific cell components and processes.
In recent years, elemental imaging of biological samples using laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) is gaining more and more importance. Improvements concerning both spatial resolution (down to 1 µm) and signal-to-background ratio due to low-dispersion LA chambers make LA-ICP-MS particularly interesting for single cell analysis.
Here LA-ICP-MS was applied for the imaging of individual cells to study the uptake and intracellular processing of metal-containing nanostructures. The cells were incubated with different NPs under varying experimental conditions and afterwards fixed with para-formaldehyde and dried for LA analysis. High-spatial resolution LA-ICP-MS was achieved by careful optimisation of the laser ablation parameters.
Our findings show, that LA-ICP-MS is applicable to localize NP aggregates within cellular compartments. The uptake efficiency depends strongly on the physicochemical properties of the nanostructures as well as on the incubation conditions like concentration and incubation time.
The results demonstrate the potential of LA-ICP-MS providing insight into nanoparticle-cell interaction dependent on experimental parameters.
In recent years, elemental imaging of biological samples like tissue thin sections using laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) is gaining more and more importance. Improvements concerning spatial resolution as well as signal-to-background ratio due to low-dispersion sample chambers make LA-ICP-MS also interesting for single cell analysis.
To evaluate the interaction of nanoparticles (NPs) with cells LA-ICP-MS was applied for the imaging of individual cells. Our findings show, that NP aggregates can be localized within cellular compartments. The uptake efficiency depends strongly on the physico-chemical properties of the nanostructures (size, chemical composition, surface modification), as well as on the incubation conditions (concentration, time).
Moreover, LA-ICP-MS is increasingly becoming an important complementary technique in bioanalysis by using element-tagging strategies to determine biomolecules indirectly. Based on the specific binding between antibodies and their corresponding antigens, proteins and peptides can be detected in tissue or cells using tagged antibodies. As artificial tags metal chelates loaded with lanthanides, polymer-based elemental tags or metal-containing nanoparticles can be used. Thereby LA-ICP-MS is a sensitive detection tool for multiplexed immuno-histochemistry of tissue and cell samples.
Our results demonstrate the potential of LA-ICP-MS to investigate the distribution of naturally occurring elements, administered agents as well as biomolecules by using metal-tagged antibodies.
Many current nanomaterials can serve as contrast agents in cellular or tissue imaging, drug delivery vehicles or therapeutics, whereas others can cause toxic effects. In order to evaluate nano-bio interactions, the number of nanoparticles (NPs) inside cells as well as their localisation within cellular substructures is of particular interest. The cellular uptake depends on the primary characteristics of the NPs (e.g. size, shape, surface coating) and on the cell type.
Laser ablation inductively coupled plasma mass spectrometry (LA‑ICP‑MS) is more and more used to study the NP pathway from uptake, via intracellular processing up to cell division. High-spatial resolution laser ablation at single cell level is achieved using novel low-dispersion LA chambers and by careful optimisation of laser energy, ablation frequency and scan speed at small laser spot sizes down to 1 µm. Different examples from BAM, Division 1.1 and cooperation partners using LA-ICP-MS to localize and quantify metal-containing nanoparticles are shown. The results demonstrate the potential of LA-ICP-MS providing insight into NP uptake, intracellular distribution and cell-to-cell variation.
Laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) is nowadays an established multi-elemental analysis and mapping technique. It was shown that LA-ICP-MS can visualize the elemental distribution within tissue thin sections or cell samples. Quantification is possible by using appropriate matrix-matched calibration samples. Besides naturally occurring elements and metals from contrast agents, biomolecules using metal-tagged antibodies were detected in different bio-medical samples. By combining the results with findings from histology, magnetic resonance imaging (MRI) and other techniques disease related changes like alterations of the extracellular matrix can be investigated.
In chemical elements with three or more stable isotopes, mass-dependent stable isotope fractionation is expressed by co-varying isotope ratios. In the three-isotope space ((δ’m2/δ’m1)/(( δ’m3/δ’m1)) these plot along a line with a slope (β), the so called ‘terrestrial fractionation line’. This partitioning of stable isotopes results from both kinetic and equilibrium reactions that are characterized by specific β-values.
For the natural range of isotope ratios of ‘novel’ stable isotope systems such as Si, Mg, Fe, Zn, Cu this information cannot be accessed because samples fall close to the delta-zero standard where the current measurement precision is too low to resolve small differences in β. We present a new approach to resolve deviations from a reference slope β by standard-sample bracketing against material offset from the natural range. We use this approach to explore the isotope fractionation mechanism in the mammalian food web. We have analyzed Mg stable isotope ratios in bone bioapatite of herbivore, omnivore and carnivore mammals. Positive shifts in δ26/24Mg along the trophic chain (from herbivore to carnivore) together with β= 0.513 suggest the presence of two isotope fractionation mechanisms operating during biomineralization. While positive shifts in δ26/24Mg are in favor of equilibrium isotope fractionation process, the proximity of β to the theoretically calculated β(kinetic) of typically 0.511 suggests the presence of a second component that fractionates stable isotopes kinetically. The herein presented approach is applicable to any element with 3+ stable isotopes analyzed by multi-collector inductively coupled plasma mass spectrometry.
In chemical elements with three or more stable isotopes, mass-dependent stable isotope fractionation yields correlated isotope ratios, m2/m1 and m3/m1. In three-isotope space, i.e. in a δ’m2/δ’m1 vs. δ’m3/δ’m1 plot, data align along a slope θ, the so called ‘triple isotope fractionation exponent’ that scales the two isotope ratios. Theoretical calculations predict small differences in θ for kinetic- and equilibrium isotope fractionation (Young et al. 2002) and thus the precise measurement of θ allows constraining the reaction mechanism. However, due to an apparent lack of precision of stable isotope analysis by MC-ICP-MS, θ is merely used as analytical quality control, i.e. for demonstration that samples and standards plot within their analytical precision in the range of theoretical θ-values originating in δ-zero.
We show how θ can be determined precisely enough by MC-ICP-MS to distinguish kinetic- and equilibrium isotope fractionation, even when isotopic differences between samples are low. For low magnitudes of isotope fractionation, we exploit new, isotopically fractionated isotope standard materials (Vogl et al. 2016). We determine quality norms regarding interferences and measurement conditions to warrant trueness and to maximize precision. We exemplary explore the measurement of the three-isotope composition of Mg stable isotopes, budget the uncertainty of θ-values, and report the first θ-values of carbonate-water pairs and bioapatite. Our measurement approach adds a new dimension to isotope data beyond the δ-scale that has a high potential to reveal different modes of (bio)mineral precipitation in the sedimentary and biological record and thus to contribute solving conundrums in the Earth and Life Sciences.
Per- und polyfluorierte Alkylverbindungen (PFAS) sind eine Substanzklasse mit über 5200 Verbindungen. Aufgrund der Persistenz, Bioakkumulation in Nahrungsketten, Toxizität und der ubiquitären Verbreitung von PFAS zählen sie zu den „emerging pollutants“. Die PFAS-Analytik ist wegen den vielfältigen physikalisch-chemischen Eigenschaften und der sehr hohen Anzahl an PFAS eine große Herausforderung. Da es für viele Anwendungen noch ungewiss ist, welche PFAS verwendet werden, wie sie in die Umwelt gelangen und welche Transformations- bzw. Abbauprodukte entstehen, stoßen analytische Ansätze, die nur auf Einzelsubstanzen abzielen, hier an ihre Grenzen. Weiterhin wird die Analytik aufgrund der Substitution von bereits regulierten PFAS mit ständig steigenden Anzahlen an PFAS-Verbindungen in der Umwelt konfrontiert. PFAS-Summenparameter-Methoden, die ein nahezu vollständiges Abbild der PFAS-Belastungssituation wiedergeben, werden daher immer wichtiger. In unserer Studie haben wir die zwei meistverwendeten PFAS-Summenparameter, das adsorbierbare organisch gebundene Fluor (AOF) und das extrahierbare organisch gebundene Fluor (EOF), miteinander verglichen. Beide Summenparameter können zur Analyse mit entweder combustion-Ionenchromatographie (CIC) oder hochauflösender Molekülabsorptionsspektrometrie (HR-CS-GFMAS) gekoppelt werden. Hierbei diskutieren wir die Vor- und Nachteile sowohl von beiden Summenparameter- als auch beider Detektions-Methoden. Die Untersuchungen wurden mit Oberflächenwasserproben aus der Spree in Berlin durchgeführt. Neben AOF und EOF wurde auch der Gesamt-Fluorgehalt (TF) mit CIC sowie HR-CS-GFMAS bestimmt. Die Fluor-Massenbilanzierung zeigte, dass das Verhältnis AOF/TF höher als das Verhältnis EOF/TF war. Dabei machte der AOF 0.14–0.81% vom TF und der EOF 0.04–0.28% vom TF aus. Insgesamt war die neue EOF/HR-CS-GFMAS-Methode schneller, präziser und sensitiver als die bereits etablierte AOF/CIC-Methode. Beide Methoden sind vielversprechend für die zukünftige Überwachung von Umweltproben und bilden die Grundlage für mögliche Grenzwerte, die auf die Summe PFAS abzielen.
Here, we describe a fast and simple extraction method for the determination of per- and polyfluorinated alkyl substances (PFASs) utilizing extractable organic fluorine (EOF) sum parameter analysis and high resolution-continuum source-graphite furnace molecular absorption spectrometry (HR-CS-GFMAS) in soil samples. After extraction and separation of inorganic and organic fluorinated compounds, organically bound fluorinated compounds were indirectly determined via the molecular absorption of gallium mono-fluoride at 211.248 nm. The implementation of the decisions of the “Stockholm Convention on persistent organic pollutants” as well as the “Protocol on Persistent Organic Pollutants of the Convention on Long-Range Transboundary Air Pollution” of the UNECE include the reduction respectively the elimination of PFASs in the environment. Currently, regulations aim to target single compounds (mostly C8-PFAS). But the PFAS group includes over 4700 substances, which are potentially persistent and toxic, thus target analytical approaches are not suitable for a holistic approach investigating the PFAS pollutant situation. Furthermore, forbidden PFASs are substituted by short-chain PFASs, thus the number of unknow substances is steadily increasing. For this reason, sum parameter approaches are more suitable to investigate and assess the pollution situation as well as derive exposure limits. Our developed analytical method was successfully applied to determine PFASs in soil samples from a polluted site. In view of steadily increasing numbers of PFAS substances, our method will make an important contribution in assessing the pollution situation as well as support policy makers in deriving exposure limits for PFAS in the future.
Per- and polyfluorinated alkyl substances (PFASs) are a group of over 4730 individual compounds. Several PFASs are extremely persistent, bioaccumulative and toxic. The analysis of PFASs is challenging because of their various chemical and physical properties as well as the high number of compounds. Target-based approaches (e.g., LC-MS/MS) are limited to the availability of analytical grade standards and are not suitable for the analysis of new/unknown PFASs and transformation products. Therefore, PFAS sum parameter methods become increasingly important to indicate realistic PFAS pollution levels.
PFAS sum parameters display the proportion of organically bound fluorine that can either be extracted (EOF) or adsorbed to activated carbon (AOF). For the instrumental analysis of such sum parameters, a fluorine selective detector is needed. High resolution-continuum source-graphite furnace molecular absorption spectrometry (HR-CS-GFMAS) is a sensitive and highly selective tool for fluorine determination. The method is based on the in situ formation of diatomic gallium-mono fluoride (GaF) in a graphite furnace at a temperature of 1550°C. The molecular absorption of GaF can be detected at its most sensitive wavelength at 211.248 nm providing limits of quantification of c(F) 2.7 µg/L.
Here, we present an improved method for the determination of PFASs using HR-CS-GFMAS via GaF detection. The optimized method includes a Ga pretreatment as described by Gawor et al. resulting in overall lower detection limits. Furthermore, during optimization the influence of species-specific responses during HR-CS-GFMAS analysis was reduced resulting in a more accurate determination of PFAS sum parameters. To test the applicability of the improved method, we analyzed soil samples from a former fire-fighting training area combining the improved method for detection with our previously optimized extraction method for EOF determination in soils.
Per- and polyfluorinated alkyl substances (PFASs) are a group of over 4730 individual compounds. Several PFASs are extremely persistent, bioaccumulative and toxic. The analysis of PFASs is challenging because of their various chemical and physical properties as well as the high number of compounds. Target-based approaches (e.g., LC-MS/MS) are limited to the availability of analytical grade standards and are not suitable for the analysis of new/unknown PFASs and transformation products. Therefore, PFAS sum parameter methods become increasingly important to indicate realistic PFAS pollution levels.
PFAS sum parameters display the proportion of organically bound fluorine that can either be extracted (EOF) or adsorbed to activated carbon (AOF). For the instrumental analysis of such sum parameters, a fluorine selective detector is needed. High resolution-continuum source-graphite furnace molecular absorption spectrometry (HR-CS-GFMAS) is a sensitive and highly selective tool for fluorine determination. The method is based on the in situ formation of diatomic gallium-mono fluoride (GaF) in a graphite furnace at a temperature of 1550°C. The molecular absorption of GaF can be detected at its most sensitive wavelength at 211.248 nm providing limits of quantification of c(F) 2.7 µg/L.
Here, we present an improved method for the determination of PFASs using HR-CS-GFMAS via GaF detection. The optimized method includes a Ga pretreatment as described by Gawor et al. resulting in overall lower detection limits. Furthermore, during optimization the influence of species-specific responses during HR-CS-GFMAS analysis was reduced resulting in a more accurate determination of PFAS sum parameters. To test the applicability of the improved method, we analyzed soil samples from a former fire-fighting training area combining the improved method for detection with our previously optimized extraction method for EOF determination in soils.
Sediments and soils can act as sinks of species of inorganic mercury (Hg2+), while they are simultaneously sources of organic species, such as monomethylmercury (MMHg). Although the fraction of MMHg in total Hg of sediments is suggested to be only 0.1–1%, MMHg poses a threat for humans and wildlife due to its toxic properties, high bioaccumulation potential and the ability to pass the blood-brain barrier. One example of a highly Hg contaminated waterbody is the Finow Canal, the oldest artificial waterway still in operation in Germany. Here, Hg mass fractions of up to 100 µg/g were found in the sediment in previous studies. These are suggested to be associated with a chemical plant producing mercury-based seed dressings. Despite this high mass fraction of Hg, no Hg speciation studies have been conducted there up to now.
In this study, Hg speciation in sediments of Finow Canal at locations before and after the known polluted site was conducted using species-specific isotope dilution (SSID) GC-ICP-ToF-MS. Mass fractions of up to 0.41 µg/g MMHg were determined. In addition, waterbodies around the initially polluted site were investigated and elevated concentrations were also determined around 14 km downstream. For MMHg analysis, the performance of ICP-ToF-MS for SSID GC/ICP-MS was compared with ICP-Q-MS and ICP-SF-MS. Here, isotope ratio precision was similar between the tested instruments. However, the (quasi-) simultaneous detection of the whole mass spectrum will probably offer a much higher precision of ICP-ToF-MS, when more than one isotope system is used.
These results are the first evidence of the occurrence of MMHg in this region and show the need for further investigations of the whole regional ecosystem, as well as the consideration of possible measures of remediation. SSID GC-ICP-(ToF)-MS is a suitable tool for investigating species-specific (multi) isotope systems for environmental monitoring.
Per- und polyfluorierte Alkylverbindungen (PFAS) sind eine Substanzklasse bestehend aus mehreren tausenden Einzelverbindungen. Unter PFAS zählen alle Verbindungen, die mindestens eine perfluorierte Methyl- (-CF3) oder Methylen-Gruppe (-CF2-) besitzen.[1] Somit zählt auch ein großer Teil der fluorierten Medikamente, Pflanzenschutzmittel oder Biozide in die PFAS-Substanzklasse. Aufgrund der Persistenz, Bioakkumulation in Nahrungsketten, Toxizität und der ubiquitären Verbreitung von PFAS zählen sie zu den „emerging pollutants“.[2] Die PFAS-Analytik ist wegen ihrer vielfältigen physikalisch-chemischen Eigenschaften und der sehr hohen Anzahl an PFAS eine große Herausforderung. Da es für viele Anwendungen noch ungewiss ist, welche PFAS verwendet werden, wie sie in die Umwelt gelangen und welche Transformations- bzw. Abbauprodukte entstehen, stoßen analytische Ansätze, die nur auf Einzelsubstanzen abzielen, hier an ihre Grenzen. PFAS-Summenparameter-Methoden, die darauf abzielen ein möglichst vollständiges Abbild der PFAS-Belastungssituation widerzuspiegeln, werden daher immer wichtiger.
The combination of non-target analysis (NTA) based on HPLC-ESI-MS with elemental fluorine speciation analysis based on HPLC-PARCI-MS for the identification and quantification of (unknown) organofluorines in environmental samples is associated with several advantages e.g., reduced non-target data treatment workflow and quantification.
PFASs compromise persistent, bioaccumulative, and toxic properties and are hence, environmental contaminants of emerging concern. Thus, procedures for identifying potential sources of the entrance of these compounds into the environment, identification of new organofluorine species, and closing mass balances need urgent development. The intrinsic fluorine tag appears in a sizable fraction of these and other xenobiotics, making elemental speciation desirable for quantitative NTA in these areas. Current non-target approaches based on ESI-HRMS suffer from a lack of data mining algorithms for identification of PFASs with low fluorine mass percentages. Furthermore, low ionization efficiencies of the compounds hamper detection limits.
Hence, the proposed combination of simultaneous HPLC-ESI-MS and HPLC-PARCI-MS via split-stream coupling is a promising approach for environmental PFAS monitoring. Furthermore, it could serve as an important analytical procedure to set up limiting values in compliance with the desired PFAS ban of the European Union.
With the continuous release of anthropogenic pollutants into the environment, substantial risks for the human health arise. Concerning are especially persistent substances (e.g., PFAS) as they accumulate in food chains which inevitably result in the transgression of negative impact threshold levels. Environmental Analytical Chemsitry interfaces all disciplines of Risk Assessment. Therefore it is the important tool to identify, monitor, and remediate environmental pollutants. Based on the example of PFAS, a workflow to tackle environmental pollutants in a retro- and pro-spective way is shown. Within the project, the worldwide situation of environmental pollutants will be illustrated for the example of PFAS. As the major discipline to confront the problem, analytical chemistry will be shown as a key tool for contesting PFAS and creating safe-by-design materials in the future.
HR-CS-GFMAS a new screening tool for per- and polyfluoroalkyl substances (PFAS) in the environment
(2023)
Per- and polyfluorinated alkyl substances (PFASs) are a large group of anthropogenic contaminates. Concerning are especially their persistent, bioaccumulative and toxic properties. Mostly, target-based approaches (e.g., LC-MS/MS) are utilized for the analysis of PFASs in the environment. But these approaches are limited to the availability of analytical grade standards and therefore drastically underestimate the total PFAS burden. Analytical approaches based on total fluorine for PFAS sum parameter analysis become increasingly important to indicate realistic PFAS pollution levels.
PFAS sum parameters display the proportion of organically bound fluorine that can either be extracted (EOF) or adsorbed to activated carbon (AOF). For the instrumental analysis of such sum parameters, a fluorine selective detector is needed. Besides combustion ion chromatography (CIC), high resolution-continuum source-graphite furnace molecular absorption spectrometry (HR-CS-GFMAS) is a sensitive and highly selective tool for fluorine determination. The method is based on the in situ formation of diatomic gallium-mono fluoride (GaF) in a graphite furnace at a temperature of 1550°C. The molecular absorption of GaF can be detected at its most sensitive wavelength at 211.248 nm providing limits of quantification in the low µg F L-1 range.
Here, we present a comparison of total fluorine analysis methods – AOF vs. EOF and HR-CS-GFMAS vs. CIC. Therefore, surface water samples from the Spree River in Berlin, Germany were analyzed at 10 locations for total fluorine (TF), AOF and EOF. The AOF made up 0.14–0.81% of TF and the EOF 0.04–0.28% of TF while AOF concentrations were systematically higher. For the instrumental comparison, HR-CS-GFMAS was the more sensitive and precise method for fluorine analysis compared to CIC.
Per- and polyfluoroalkyl substances (PFASs) are a group of anthropogenic contaminates associated with persistent, bioaccumulative and toxic properties. Mostly, target-based approaches (e.g., LC-MS/MS) are utilized for the analysis of PFASs in the environment. Target approaches are limited to a few selected PFASs and therefore underestimate the total PFAS burden. Analytical approaches based on total fluorine for PFAS sum parameter analysis become increasingly important to indicate realistic PFAS pollution levels.
Recently high resolution-continuum source-graphite furnace molecular absorption spectrometry (HR-CS-GFMAS) turned out to be a sensitive and highly selective tool for fluorine determination. The method is based on the in situ formation of diatomic gallium-mono fluoride (GaF) in a graphite furnace at a temperature of 1550°C. The molecular absorption of GaF can be detected at its most sensitive wavelength at 211.248 nm providing limits of quantification in the low µg F/L range. HR-CS-GFMAS analysis can be combined with the extractable organically bound fluorine (EOF) approach whereas PFASs are extracted from liquid or solid samples using organic solvents and/or solid phase extraction (SPE).
In this presentation the applicability of HR-CS-GFMAS for organic fluorine analysis in various environmental sample including (1) water samples, (2) soil samples and (3) plant samples is demonstrated.
(1) We investigated EOF concentrations in water bodies in Berlin, Germany and used additional PFAS target analysis for a PFAS mass balance approach. EOF concentrations were in the expected range for an urban river system. However, downstream of an effluent discharge, the EOF increased by one order of magnitude from 40 to 574 ng F/L. Target analysis determined mostly short-chained perfluorinated carboxylic acids and sulfonic acids, which however only made up less than 10% of the EOF. This study highlights that EOF screening using HR-CS-GFMAS is useful and advantageous compared to target analysis to identify pollution sites in urban water systems.
(2) For soil samples, we optimized a fast and simple PFAS extraction method for EOF determination. The developed extraction method consists of a liquid-solid extraction without any additional SPE for fluoride removal. We investigated different soil samples using the optimized method with and without an additional SPE clean-up step and revealed a drastic underestimation of EOF mass fractions using SPE. The optimized method is a valuable screening tool for fast PFAS monitoring.
(3) For plant samples, we conducted a study on the uptake and fate of PFASs in bean plants. For PFAS mass balancing HR-CS-GFMAS analysis was combined with LC-MS/MS analysis. PFASs were spiked as mixtures of known and unknown composition. Short-chained PFASs were determined with high mass fractions mainly in the fruits of the investigated plants while long-chained PFASs were mainly determined in roots. Overall, both methods indicate comparable results with target analysis being more reliable for known PFAS contamination and EOF/HR-CS-GFMAS analysis being more valuable to identify PFAS exposure of unknown composition.
Introduction
Per- and polyfluorinated alkyl substances (PFASs) are a group of over 4730 individual compounds. Several PFASs are extremely persistent, bioaccumulative and toxic. The analysis of PFASs is challenging because of their various chemical and physical properties as well as the high number of compounds. Target-based approaches (e.g., LC-MS/MS) are limited to the availability of analytical grade standards and are not suitable for the analysis of new/unknown PFASs and transformation products. Therefore, PFAS sum parameter methods become increasingly important to indicate realistic PFAS pollution levels.
Methods
For the instrumental analysis of such sum parameters, a fluorine selective detector is needed. In our study we used high resolution-continuum source-graphite furnace molecular absorption spectrometry (HR-CS-GFMAS) which is a sensitive and highly selective tool for fluorine determination. The method is based on the in situ formation of diatomic gallium-mono fluoride (GaF) in a graphite furnace at a temperature of 1550°C. The molecular absorption of GaF can be detected at its most sensitive wavelength at 211.248 nm providing limits of quantification of c(F) 2.7 µg/L.
Results
Here, we present an improved method for the determination of PFASs using HR-CS-GFMAS via GaF detection. The optimized method includes a modifier pretreatment step using a mixture of Mg, Pd and Zr and a correction measurement using perfluorooctanoic acid. The combination of both resulted in increased accuracy and precision as well as overall lower detection limits. Furthermore, during optimization the influence of species-specific responses during HR-CS-GFMAS analysis was reduced resulting in a more accurate determination of PFAS sum parameters. To test the applicability of the improved method, we analysed soil samples from a former fire-fighting training area combining the improved method for detection with our previously optimized extraction method for extractable organically bound fluorine (EOF) determination in soils.
Innovative aspects
• Highly sensitive and selective method for fluorine/PFASs analysis based on HR-CS-GFMAS
• Increased accuracy for the determination of EOF
• Reduction of PFAS species-specific responses by optimized modifier conditions
Organotin compounds (OTCs) have been widely used in anti-fouling paints, pesticide formulations, and as stabilizers in polyvinyl chloride over the past century. In marine ecosystems, OTCs can cause severe damage to biodiversity, leading up to the extinction of vulnerable species. Due to the extensive use of tributyltin (TBT) as a biocide on ship hulls, it has been considered one of the most hazardous substances intentionally introduced into the aquatic environment. This resulted in a global ban on TBT-containing products in the 2000s. However, recent studies indicate the emerging presence of organotin pollutants.
OTCs are known to persist and accumulate in marine sediments, posing a long-term threat to the environment. These harmful substances can be set free and dispersed even after several decades. Therefore, analyzing sediment probes is imperative for a thorough monitoring of pollution. However, species-specific analysis of OTCs at required concentration levels in complex environmental matrices remains challenging. Chromatographic systems are commonly used for their analysis, but the required sample preparation is time-consuming and prone to contamination and analyte loss. The coupling of electrothermal vaporization and inductively coupled plasma-mass spectrometry (ETV/ICP-MS) demonstrates high potential as a rapid, convenient, and chemical-saving scanning tool for environmental samples.
This method enables the direct on-line fractionation of organic compounds from an inorganic fraction and provides element-specific detection at ultra-trace levels without complex sample preparation. Since OTCs are generally more toxic than ionic or elemental tin, analyzing them as a sum parameter is advantageous. Additionally, the determination of both organic and inorganic tin, rather than just organic tin, reveals valuable information about the fate of OTCs. The main challenge in obtaining accurate quantitative data using direct solid sampling techniques like as ETV/ICP-MS is applying a suitable calibration strategy. Our isotope dilution approach overcomes matrix effects in ETV/ICP-MS analysis and is compatible with commercial systems.
In der klinischen Diagnostik werden für zytometrische Messverfahren bereits eine Reihe von Reagenzien eingesetzt zur Markierung von Antikörper eingesetzt, um die Detektion von Biomarkern mittels Fluoreszenz- oder Flugzeitmassenspektrometrie zu ermöglichen.
Seit kurzem ist auch eine Imaging Mass Cytometry Kombination direkt erhältlich, wodurch der Nachweis von Biomarkern in Gewebeschnitten erreicht werden kann. Dazu wird eine Kopplung von Laser Ablation und induktiv gekoppeltem Plasma Massenspektrometrie eingesetzt, wobei ähnlich der Massenzytometrie, zuvor Antikörper mit Metallen markiert, und im Anschluss mit dem Gewebeschnitt inkubiert werden. Durch die hohe Ortsauflösung können die Biomarker lokalisiert, und zukünftig vielleicht auch quantifiziert werden.
Insbesondere Lanthanide eignen sich als Markierungsmetalle, da sie einen niedrigen Untergrund und chemisch ähnliches Verhalten zueinander aufweisen. Allein durch diese Elemente können bereits etwa 15 Parameter unterschieden werden, was durch isotopenreine Standards weiter gesteigert werden kann.
Vom Markierungsgrad abhängig werden unterschiedlich viele Metalle am Antikörper gebunden, und beeinflussen so die Sichtbarkeit im ICP-MS. Nanopartikel könnten daher eine deutliche Steigerung der Sensitivität bewirken. GdVO4 Nanokristalle scheinen bisher sehr vielversprechend und bieten neben multiparametrischen Anwendungen auch Multimodalität.
Die Synthese der Nanokristalle zeigte hohe Homogenität und Reproduzierbarkeit in Partikelgröße in der Zusammensetzung. Ein erstes Experiment mit einer Zellkultur konnte bereits die effiziente Markierung der Zellen unter Beweis stellen, wobei durch hohe Signalstärke auch subzelluläre Auflösung in der LA-ICP-MS erreicht werden konnte.
Lithium exists in two stable isotopes, 6Li and 7Li. The ratio of these in every ore varies depending on the geological history of the sample, thus providing a tool for fingerprinting the distinct origin of Li containing samples. Determination of the exact isotope ratio for e.g. designation of provenance today relies on expensive and bulky instrumentation such as multi `collector inductively coupled plasma mass spectrometry` (MC-ICP-MS). These instruments, however, are known to bear pitfalls in the characterization of particular elements including Lithium. BAM recently developed two alternative analytical devices for this task, solely relying on inexpensive optical spectroscopy in combination with state-of-the-art multivariate data analysis such as Machine learning algorithms. Both techniques have been comprehensively studied using certified reference materials and comparing the results to MC-ICP-MS results and could be shown to result in comparable figures of merit, paving the way for a more general accessibility to provenance determination instrumentation. The results also pave the way towards even further simplification of the laboratory infrastructure demands and to further include additional elements into the isotopic fingerprinting methodology.
Luminescent nanocrystals like core/shell semiconductor quantum dots and lanthanide doped nanophosphors as well as gold nanoclusters with emission in the visible (vis) and particularly in the near infrared (NIR) and short wavelength infrared (SWIR) region have been increasingly used as reporters in the life sciences and for bioimaging studies in the last years. This has led to sophisticated core-shell particle architectures of different chemical composition utilizing semiconductor quantum dots and lanthanide-based nanocrystals and initiated the design of gold nanoclusters with different ligands. In addition, this led to an increasing number of quantitative spectroscopic studies focusing on the key performance parameter photoluminescence quantum yield to identify optimum particle structures. In the following, an overview of different classes of nanocrystalline emitters and their photophysics is provided and examples for the absolute characterization of the photoluminescence properties of these different vis/NIR/SWIR emitters are shown including excitation power density-dependent studies on the ensemble and single particle level. Also, the impact of such measurements on a profound mechanistic understanding of the underlying nonradiative deactivation pathways is highlighted as required for reporter design.
Introduction: The influence of copper, iron and zinc concentrations on the formation of ß-amyloid plaques and neurofibrillary tangles in Alzheimer’s disease (AD) is widely discussed in the community. The results from human and animal studies so far are mixed with some studies showing a correlation and others not. From a number of studies, it is known that disease state and isotopic composition of essential elements can be coupled.
Aim: The aim of the study was to identify changes in element content and isotopic composition in two transgenic mouse models used in AD research compared to their genetic WT relatives and to establish whether element content and isotopic signature between different laboratories is comparable.
Methods: ß-amyloid (5xFAD) and tau overexpressing (L66) mice together with their matching wild-types were bred at dedicated facilities in accordance with the European Communities Council Directive (63/2010/EU). Serum and brain were sampled after sacrifice and the samples distributed among the participants of the study. The tissues were acid digested for total element determination and high-precision isotope ratio determination. Element content was determined by either sector-field or quadrupole-based inductively coupled plasma mass spectrometry (ICPMS). For the determination of isotope ratios multi-collector ICPMS was used.
Results: Total copper content was significantly higher for L66 and their matched WT compared to 5xFAD and WT. Brains of L66 mice contained more Fe in brain than their WT, Zn and Cu were not significantly different between L66 and WT. Whereas 5xFAD mice had a slightly lower Cu and slightly higher Zn concentration in brain compared to WT. The isotopic signature in brain of L66 mice for Fe was different from their controls, whereas Zn isotope ratios were influenced in 5xFAD mice compared to their WT. The Cu isotopic ratio did not seem to be influenced in either strain. In serum, the shifts were less pronounced.
Conclusion: Even though neither Tau-protein nor amyloid precursor protein are known to be metal-dependent / -containing proteins, the overexpression of both influences the Fe, Cu and Zn metabolism in brain and to some extent also in serum as can be seen not only using total element determination but probably more clearly studying the isotopic signature of Fe, Cu and Zn.
Introduction: The influence of copper, iron and zinc concentrations on the formation of ß-amyloid plaques and neurofibrillary tangles in Alzheimer’s disease (AD) is widely discussed in the community. The results from human and animal studies so far are mixed with some studies showing a correlation and others not. From a number of studies, it is known that disease state and isotopic composition of essential elements can be coupled.
Aim: The aim of the study was to identify changes in element content and isotopic composition in two transgenic mouse models used in AD research compared to their genetic WT relatives and to establish whether element content and isotopic signature between different laboratories is comparable.
Methods: ß-amyloid (5xFAD) and tau overexpressing (L66) mice together with their matching wild-types were bred at dedicated facilities in accordance with the European Communities Council Directive (63/2010/EU). Serum and brain were sampled after sacrifice and the samples distributed among the participants of the study. The tissues were acid digested for total element determination and high-precision isotope ratio determination. Element content was determined by either sector-field or quadrupole-based inductively coupled plasma mass spectrometry (ICPMS). For the determination of isotope ratios multi-collector ICPMS was used.
Results: Total copper content was significantly higher for L66 and their matched WT compared to 5xFAD and WT. Brains of L66 mice contained more Fe in brain than their WT, Zn and Cu were not significantly different between L66 and WT. Whereas 5xFAD mice had a slightly lower Cu and slightly higher Zn concentration in brain compared to WT. The isotopic signature in brain of L66 mice for Fe was different from their controls, whereas Zn isotope ratios were influenced in 5xFAD mice compared to their WT . The Cu isotopic ratio did not seem to be influenced in either strain. In serum, the shifts were less pronounced.
Conclusion: Even though neither Tau-protein nor amyloid precursor protein are known to be metal-dependent / -containing proteins, the overexpression of both influences the Fe, Cu and Zn metabolism in brain and to some extent also in serum as can be seen not only using total element determination but probably more clearly studying the isotopic signature of Fe, Cu and Zn.
Determination of absolute (SI‐traceable) isotope ratios: The use of Gravimetric Isotope Mixtures
(2023)
The presentation is brief overview on how to use gravimetric isotope mixtures to determine SI traceable isotope ratios. There is no mass spectrometer on earth that directly measures isotope ratios. Mass spectrometers will always measure signal intensity ratios instead. The actual problem is that the measured intensity ratios differ more or less from the isotope ratios. The difference can be up to more than 10 % in case of lithium while it‘s below 1 % in case of the heavier elements like lead or uranium. Consequently, the signal intensity ratios are expressed for example in V/V depending on the type of mass spectrometer you are using, while the isotope ratios are expressed in mol/mol. This phenomenon is called Instrumental Isotopic Fractionation (or short IIF) but the more common name is still mass bias (even though this name is not entirely correct). To convert the measured into the isotope ratio usually a simple multiplication with a so-called correction (or short K) factor is done. Therefore, the problem is to determine the K factor. In absence of isotope reference materials the golden route is via gravimetric isotope mixtures, which will be explained within the presentation.
Gegenstand der vorzustellenden Arbeiten ist die Prüfung der Umweltbeständigkeit und -verträglichkeit von Materialien und Produkten hinsichtlich der Emission von potenziellen Schadstoffen in die Umwelt. Hierzu werden chemisch-physikalische Einflüsse (Bewitterung) und mikrobielle Beanspruchungen an Modellmaterialien evaluiert. So werden die Freisetzungsraten von Schadstoffen in Abhängigkeit der Beanspruchung beschrieben. Als Modellmaterialien kommen die Polymere Polystyrol (PS) und Polypropylen (PP) zum Einsatz, die jeweils mit polybromierten Flammschutzmitteln (PBFSM) versehen sind. Synergistische Effekte der Bewitterungsparameter und der mikrobiologischen Beanspruchung sollen dabei ebenso betrachtet werden, wie die gezielte Alterung. Auch findet eine Beschreibung des Verhaltens der ausgetragenen Schadstoffe in den Umweltkompartimenten Boden oder Wasser statt. Hier sind mit Hilfe der zu entwickelnden Screening- und non-Target-Analyseverfahren die Transformation und der Metabolismus durch Mikroorganismen zu beschreiben. Auch soll mit Hilfe der RFA und der LA-ICP-MS die Abreicherung der PBFSM in den Modellmaterialien beschrieben werden. Aus den Ergebnissen sollen Korrelationen zwischen den künstlichen Alterungsverfahren und realen Szenarien abgeleitet werden.
Environmental sustainability and –stability of Materials concerning the Migration of pollutants
(2018)
MaUS is an acronym for ”Material und Umweltsimulationen“. Plastics are in the focus of environmental politics due to their long-term behaviour and therefore to their persistence. Not only that they appear as visible contaminants in the sea and on the beach, but their unknown behaviour concerning their additives as well as the related transformation products are anxious. Therefore, we wish to establish a certified reference method to provide a method for testing plastics.
Aim of this project is the development of fast motion standard reference methods for testing plastics regarding to their environmental compatibility. To establish these testing methods, we use polystyrene (PS) and polypropylene (PP) with environmental relevant brominated flame retardants, known for their persistent bioaccumulative and toxic (PBT) properties. In case of PS the material contains 1 wt% of 1,2,5,6,9,10-hexabromocyclododecan (HBCD) and in case of PP 0.1 wt% bromodiphenylether (BDE-209), which is known as a substance of very high concern (SVHC). Furthermore, we use polycarbonate (PC), which is still used as material in baby flasks and releases Bisphenol A (BPA), an estrogenic active substance.
As an additional material PTFE is used for its importance as a source for two ubiquitous environmental substances (PFOS and PFOA), whose toxicological effects are still incompletely known.
The focus in this current work is set on the transfer of potential pollutants out of applied materials mentioned above into environmental compartments like water or soil. Here an accelerated aging concept should be developed to shortened time consuming natural processes. For these resulting simulations we use a programmable weathering chamber with dry and wet periods and with high and low temperatures. These programmes run for several weeks and according to a defined sampling schedule we take water samples, run a clean-up procedure by SPE (Molecular imprinted polymers (MiPs) resp. polymer-based cartridges (Waters Oasis HLB)) and analyse them by HPLC-UV resp. LC-MS/MS. Of most interest in case of flame retardants are photocatalytic transformation products. Therefore, we conduct a non-target-screening resp. a suspected target-screening by LC-MS/MS and HRMS.
Gegenstand der vorzustellenden Arbeiten ist die Prüfung der Umwelt-beständigkeit und -verträglichkeit von Materialien und Produkten hinsichtlich der Emission von potenziellen Schadstoffen in die Umwelt. Hierzu werden chemisch-physikalische Einflüsse (Bewitterung) und mikrobielle Beanspruchungen an Modellmaterialien evaluiert. So werden die Freisetzungsraten von Schadstoffen in Abhängigkeit der Beanspruchung beschrieben. Als Modellmaterialien kommen die Polymere Polystyrol (PS) und Polypropylen (PP) zum Einsatz. Synergistische Effekte der Bewitterungsparameter und der mikrobiologischen Beanspruchung sollen dabei ebenso betrachtet werden, wie die gezielte Alterung. Auch findet eine Beschreibung des Verhaltens der ausgetragenen Schadstoffe (polybromierte Flammschutzmittel) in den Umweltkompartimenten Boden oder Wasser statt. Hier sind mit Hilfe der zu entwickelnden Screening- und non-Target-Analyseverfahren die Transformation und der Metabolismus durch Mikroorganismen zu beschreiben. Aus den Ergebnissen sollen Korrelationen zwischen den künstlichen Alterungsverfahren und realen Szenarien abgeleitet werden.
Gegenstand des Projekts ist die Prüfung der Umweltbeständigkeit und -verträglichkeit von Materialien und Produkten hinsichtlich der Emission von potenziellen Schadstoffen in die Umwelt. Hierzu werden chemisch-physikalische Einflüsse (Bewitterung) und mikrobielle Beanspruchungen an Modellmaterialien evaluiert. So werden die Freisetzungsraten von Schadstoffen in Abhängigkeit der Beanspruchung beschrieben. Als Modellmaterialien kommen die Polymere Polycarbonat, Polytetrafluorethylen, Polystyrol und Polypropylen zum Einsatz. Synergistische Effekte der Bewitterungsparameter und der mikrobiologischen Beanspruchung sollen dabei ebenso betrachtet werden, wie die gezielte Alterung. Auch findet eine Beschreibung des Verhaltens der ausgetragenen Schadstoffe in den Umweltkompartimenten Boden oder Wasser statt. Hier sind mit Hilfe der zu entwickelnden Screening- und non-Target-Analyseverfahren die Transformation und der Metabolismus durch Mikroorganismen zu beschreiben. Aus den Ergebnissen sollen Korrelationen zwischen den künstlichen Alterungsverfahren und realen Szenarien abgeleitet werden, die es gestatten, Schnellprüfverfahren zu etablieren, die die Simulation der realen Beanspruchungen im Zeitraffermodell anwendbar machen. Somit sollen standardisierbare Schnellbeanspruchungs-verfahren erarbeitet werden, die als Prüfeinrichtungen etabliert werden und von externen Auftraggebern zur Prüfung der Umweltbeständigkeit und -verträglichkeit von neuen Materialien genutzt werden können. Die Umweltwirkungen (chemisch-physikalisch und mikrobiologisch) sollen so definiert eingesetzt werden, dass eine reproduzierbare Prüfung möglich wird. Aus diesen Verfahren und Methoden sollen Normen abgeleitet werden, die eine standardisierte Materialprüfung ermöglichen.
Environmental sustainability and –stability of materials concerning the migration of pollutants
(2019)
In addition to previously reported results on the accelerated weathering of polystyrene samples (PS) containing 1 wt. % hexabromocyclododecane (HBCD), we present the first results of our investigations of polypropylene samples (PP) containing 0.1 wt. % BDE-209. All studied polymer samples were exposed to a defined weathering schedule in a climate chamber in accordance to regulation EN ISO 4892-3:2006. For the determination of BDE-209 in the collected raining water the samples were prepared in accordance to a validated protocol. Before the analyses each sample was spiked with isotopically labeled BDE-209. Subsequently the samples were extracted with isooctane. The obtained extracts were concentrated, and the resulting solutions were analyzed by GC/MS. Additionally, the total bromine content was monitored for the weathered and untreated samples using laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) and X-ray fluorescence analysis (XRF) as a non-destructive and rapid method. In general, the resulting data from the accelerated weathering will be compared to those from the natural weathering experiments. Here, the surfaces of the test pieces were analyzed by LA-ICP-MS and XRF as well. Moreover, soil bed tests were conducted in a well characterized model soil. This soil (boulder-clay, sand with 12 % loam, particle size in total 0.2-4 mm) is filled in a free-draining basin inside of an air-conditioned cellar. In this manner, TOC, water capacity and humidity are recorded parameters. To induce a leaching process from the samples by the raining water, the target water content is calculated to 8%. The actual humidity is measured by a tensiometer, assuring the duration of the raining period. A defined humidity is a fundamental parameter for a biological activity in the soil. The test polymers were placed up to the half in the soil. Microbial activity of the soil is monitored by a reference polymer (polyurethane) and should induce the release of HBCD and BDE-209 out of the test materials. These released analytes will be captured by passive samplers (silicone tubes) placed in a distinct distance to the polymer samples in the soil. The soil bed experiments are complementary to the weathering experiments due to the biological activity in the soil.
In addition to previously reported results on the accelerated weathering of polystyrene samples (PS) containing 1 wt.% hexabromocyclododecane (HBCD), we present the first results of our investigations of polypropylene samples (PP) containing 0.1 wt.% BDE-209. All studied polymer samples were exposed to a defined weathering schedule in a climate chamber in accordance to regulation EN ISO 4892-3:2006. For the determination of BDE-209 in the collected raining water the samples were prepared in accordance to a validated protocol. Before the analyses each sample was spiked with isotopically labeled BDE-209. Subsequently the samples were extracted with isooctane. The obtained extracts were concentrated, and the resulting solutions were analyzed by GC/MS. Additionally, the total bromine content was monitored for the weathered and untreated samples using laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) and X-ray fluorescence analysis (XRF) as a non-destructive and rapid method. In general, the resulting data from the accelerated weathering will be compared to those from the natural weathering experiments. Here, the surfaces of the test pieces were analyzed by LA-ICP-MS and XRF as well. Moreover, soil bed tests were conducted in a well characterized model soil. This soil (boulder-clay, sand with 12 % loam, particle size in total 0.2-4 mm) is filled in a free-draining basin inside of an air-conditioned cellar. In this manner, TOC, water capacity and humidity are recorded parameters. To induce a leaching process from the samples by the raining water, the target water content is calculated to 8%. The actual humidity is measured by a tensiometer, assuring the duration of the raining period. A defined humidity is a fundamental parameter for a biological activity in the soil. The test polymers were placed up to the half in the soil. Microbial activity of the soil is monitored by a reference polymer (polyurethane) and should induce the release of HBCD and BDE-209 out of the test materials. These released analytes will be captured by passive samplers (silicone tubes) placed in a distinct distance to the polymer samples in the soil. The soil bed experiments are complementary to the weathering experiments due to the biological activity in the soil.
Gegenstand der vorzustellenden Arbeiten ist die Prüfung der Umweltbeständigkeit und -verträglichkeit von Materialien und Produkten hinsichtlich der Emission von potenziellen Schadstoffen in die Umwelt. Hierzu werden chemisch-physikalische Einflüsse (Bewitterung) und mikrobielle Beanspruchungen an Modellmaterialien evaluiert. So werden die Freisetzungsraten von Schadstoffen in Abhängigkeit der Beanspruchung beschrieben. Als Modellmaterialien kommen die Polymere Polystyrol (PS) und Polypropylen (PP) zum Einsatz, die jeweils mit polybromierten Flammschutzmitteln (PBFSM) versehen sind. Synergistische Effekte der Bewitterungsparameter und der mikrobiologischen Beanspruchung sollen dabei ebenso betrachtet werden, wie die gezielte Alterung. Auch findet eine Beschreibung des Verhaltens der ausgetragenen Schadstoffe in den Umweltkompartimenten Boden oder Wasser statt. Hier sind mit Hilfe der zu entwickelnden Screening- und non-Target-Analyseverfahren die Transformation und der Metabolismus durch Mikroorganismen zu beschreiben. Auch soll mit Hilfe der RFA und der LA-ICP-MS die Abreicherung der PBFSM in den Modellmaterialien beschrieben werden. Aus den Ergebnissen sollen Korrelationen zwischen den künstlichen Alterungsverfahren und realen Szenarien abgeleitet werden.
This is the first time that PE frits were used to quantify sulfur in copper and its alloys by isotope dilution combined with LA-ICP-MS: an alternative approach for sample preparation. The following properties of the PE frit meet the requirements for isotope dilution LA-ICPMS:: porous material, thermo plastic (melting point >100oC), chemical resistance (nitric acid >70%) and high adsorption efficiency. The breakthrough, however, as a support material, especially when comparing the PE frit with other materials such gelatin or sodium silicate is the low blank, which is only two times of the gas flow blank (2.3-4.0 x 104 cps). Additionally, the porosity of the frit was considered, as it directly affects the adsorption efficiency for the sample solution, which is present in the cavities of the frit.
Adsorption efficiency was studied by depositing sulfur standards with varying sulfur amounts (0, 2, 5, 10, 20, 40 and 80 µg S) on the frits. The remaining sulfur which was not absorbed by the frit was rinsed off and was measured by ICP-MS. This indirect method shows that more than 99.5 % of the loaded sulfur was absorbed by the frit. Such high absorption efficiency is completely sufficient for a support material to be used in LA-ICP-IDMS. The so prepared frits whith increasing sulfur amount were measured by LA-ICP-MS showing a good linearity between 0 µg S and 40 µg S whit a correlation coefficient r2 of 0.9987 and sensitivy of 3.4x104 cpsµg-1 for 32S.
Three copper reference materials produced by BAM were selected to develop and validate the LA-ICP-IDMS procedure. The IDMS technique was applied to these samples as follows: the samples were spiked, dissolved, digested and then the digest was adsorbed on the frits.
This is the first time that PE frits were used to quantify sulfur in copper and its alloys by isotope dilution combined with LA-ICP-MS: an alternative approach for sample preparation. The following properties of the PE frit meet the requirements for isotope dilution LA-ICPMS: porous material, thermo plastic (melting point >100°C), chemical resistance (nitric acid >70%) and high adsorption efficiency. The breakthrough, however, as a support material, especially when comparing the PE frit with other materials such gelatin or sodium silicate is the low blank, which is only two times of the gas flow blank (2.3-4.0 x 10⁴ cps). Additionally, the porosity of the frit was considered, as it directly affects the adsorption efficiency for the sample solution, which is present in the cavities of the frit.
Adsorption efficiency was studied by depositing sulfur standards with varying sulfur amounts (0, 2, 5, 10, 20, 40 and 80 µg S) on the frits. The remaining sulfur which was not absorbed by the frit was rinsed off and was measured by ICP-MS. This indirect method shows that more than 99.5 % of the loaded sulfur was absorbed by the frit. Such high absorption efficiency is completely sufficient for a support material to be used in LA-ICP-IDMS. The so prepared frits with increasing sulfur amount were measured by LA-ICP-MS showing a good linearity between 0 µg S and 40 µg S with a correlation coefficient r2 of 0.9987 and sensitivity of 3.4x10⁴ cps µgˉ¹ for 32S.
Three copper reference materials produced by BAM were selected to develop and validate the LA-ICP-IDMS procedure. The IDMS technique was applied to these samples as follows: the samples were spiked, dissolved, digested and then the digest was adsorbed on the frits.
Microbiologically influenced corrosion (MIC) is a highly unpredictable process dictated by the environment, microorganisms, and the respective electron source. Interaction pathways between cells and the metal surface remain unclear. The development of this novel single cell-inductively coupled plasma-time of flight-mass spectrometry analytical method and a MIC-specific staining procedure facilitate the investigation of steel-MIC interactions. With this it is possible to analyze the multi-elemental fingerprint of individual cells. The detection method revealed elemental selectivity for the corrosive methanogenic archaeal strain Methanobacterium-affiliated IM1. The interface between material and environmental analysis thus receives special attention, e.g., when considering MIC on solid steel. Hence, the possible uptake of individual elements from different steel samples is investigated. Results showed the cells responded at a single-cell level to the different types of supplemented elements and displayed the abilities to interact with chromium, vanadium, titanium, cobalt, and molybdenum from solid metal surfaces. The information obtained will be used in the future to elucidate underlying mechanisms and develop possible material protection concepts, thus combining modern methods of analytical sciences with materials research.
Inductively coupled plasma-time of flight-mass spectrometry (ICP-ToF-MS) enables the analysis of the multi-element fingerprint of individual cells due to a (quasi-)simultaneous detection of about 70 elements of the periodic table. The interface between material and environmental analysis thus receives special attention, e.g., when considering corrosion processes. Microbiologically influenced corrosion (MIC) is a highly unpredictable phenomenon due to the influence of the environment, microbial communities involved and the respective electron source. However, the interaction pathway between cells and the metal surface remains unclear. The development of the MIC-specific ICP-ToF-MS analytical method presented here, in combination with the investigation of steel-MIC interactions, contributes significantly to progress in instrumental MIC analysis and will enable clarification of the processes taking place. For this, a MIC-specific staining procedure was developed which ensures the analysis of intact cells. It allows the studies of archaea at a single cell level which is extremely scarce compared to other well characterized organisms. Additionally, the single cell ICP-ToF-MS is used for the analysis of archaea involved in MIC of steel. Hence, the possible uptake of individual elements from different steel samples is investigated - the information obtained will be used in the future to elucidate underlying mechanisms and develop possible material protection concepts, thus combining modern methods of analytical sciences with materials research.
Materials are key for our modern communities. In particular metals play important roles in all areas of our daily life - from building materials to high tech products.
Due to the increasing consumption of metals and corresponding waste production, an elevated release into the environment takes place. Furthermore, metals in direct contact with the environment undergo corrosion leading to a release into the (aquatic) environment. Thus, lifespan of products/buildings are substantially reduced – hence unnecessary economic costs arise. Thus, research in this regard is needed within the force field of metal/material - environment.
Evaluating the environmental impact of materials as well as developing “safe” materials, new analytical methods are highly needed. One promising powerful tool is single cell-ICP-ToF-MS for multi-elemental analysis on a single cell/organism level.
Within this presentation the concept, strength as well as challenge of single cell-ICP-MS are briefly introduced. Two application examples are presented: (i) assessing the environmental impact of metals and (ii) the impact of the environment on metal-based materials and the derivation of potential environmental-friendly material protection strategies. These applications highlight the strength of new analytical approaches to explore the durability and safety of newly developed materials. Thus, analytical chemistry is one corner stone to transformation of modern society into circular economy (CEco).
(i) Diatoms are located at the bottom of the food chain. Thus, toxicological relevant metals taken up by diatoms possibly accumulate within the food web causing harmful effects. Diatoms are common test system in ecotoxicology. To investigate potential metal uptake and effects, we developed an on-line single cell-ICP-ToF-MS approach for multi-elemental diatom analysis. Our approach is a new potential tool in ecotoxicological testing for metal-based materials.
(ii) Next to classical corrosion processes, microorganisms are responsible for so called microbially influenced corrosion (MIC). MIC is a highly unpredictable process relying on interaction pathways between cells and the metal surface. Sheding light on MIC processes and derivate potential protection strategies, we applied single cell-ICP-ToF-MS for MIC research on a single bacteria/archaea level. It turned out that microorganism are taking up particular metals from alloys - thus, single bacteria-ICP-ToF-MS will enable development of corrosion protection strategies.
In many scientific fields, isotopic analysis can offer valuable information, e.g., for tracing the origin of food products, environmental contaminants, forensic and archaeological samples (provenance determination), for age determination of minerals (geochronological dating) or for elucidating chemical processes. Up to date, typically bulk analysis is aimed at measuring the isotopic composition of the entire elemental content of the sample. However, the analyte element is usually present under the form of different elemental species. Thus, separating species of interest from one another and from matrix components prior to isotope ratio measurements can provide species-specific isotopic information, which could be used for tracing the origin of environmental pollutants and elucidation of (environmental) speciation. Using on-line hyphenations of separation techniques with multicollector-ICP-MS (MC-ICP-MS) can save time and effort and enables the analysis of different species during a single measurement.
In this work, we developed an on-line hyphenation of CE with multicollector-ICP-MS (CE/MC-ICP-MS) for isotopic analysis of sulfur species. With this method, the isotopic composition of sulfur in sulfate originating from river water could be analyzed without sample preparation. The results were compared with data from off-line analysis of the same samples to ensure accuracy. The precision of the results of the on-line measurements was high enough to distinguish the rivers from one another by the isotopic signature of the river water sulfate. Next to environmental applications, a current field is species-specific isotopic analysis of biomolecules, as sulfur is the only covalently bound constituent of proteins which can be analyzed by MC-ICP-MS. Data analysis of transient signals in terms of isotope ratio determination is further issue - we developed a small free accessible App allowing for fast data analysis taking relevant aspects (e.g., mass bias correction, peak picking, …) into account.
Materials in contact with the environment release e.g., metal-ions, elemental species and/or (nano-)particles. Once these species and/or particles are released, they are ingested by organisms and cells and thus, might have a negative impact on the environment. Thus, identification as well as quantification of potentially harmful substances is of utmost importance and highly needed to assess ecotoxicological impact of (emerging) pollutants.
The oral presentation provides an overview on the power of elemental analytical techniques, in particular ICP-MS as well as HR-CS-GFMAS in environmental research. Current research topics from Division 1.1 @ BAM - Inorganic trace analysis will be highlighted:
i) Elemental Speciation & Isotope analysis - new tools:
Among elemental species separation and quantification, one of the main challenges in environmental elemental speciation analysis is the distinction between anthropogenic and natural elemental species. The on-line combination of elemental speciation and isotope analysis combines “the best from both worlds” - species specific isotopic information becomes available.
As an application example the analysis of current anti-fouling agents via CE/MCICP-MS will be highlighted.
ii) HR-CS-GFMAS for PFC analysis:
Per- and polyfluorinated compounds (PFC) are emerging contaminants in particular in soil and surface water samples. Due to the large number of compounds (>4700), target analytical methods are not sufficient and sum parameter methods for organically bound fluorine are highly needed.
High resolution-continuum source-graphite furnace molecular absorption spectroscopy (HR-CS-GFMAS) based methods for organically bound fluorine analysis will be presented. Application examples (soil and surface water) will be highlighted.
iii) Single cell-ICP-ToF-MS - ecotox. assessment:
Single cell and single organism analysis for e.g. ecotoxicological/medicinal assessment are hot topics in the research field of ICP-MS. In particular ICP-ToF-MS is a powerful, emerging techniques in terms of single cell/particle analysis.
Automated single cell/diatom-ICP-ToF-MS as a potential tool in ecotoxicological testing will be presented.
In many scientific fields, isotopic analysis can offer valuable information, e.g., for tracing the origin of food products, environmental contaminants, forensic and archaeological samples (provenance determination), for age determination of minerals (geochronological dating) or for elucidating chemical processes. Up to date, typically bulk analysis is aimed at measuring the isotopic composition of the entire elemental content of the sample. However, the analyte element is usually present under the form of different species. Thus, separating species of interest from one another and from matrix components prior to isotope ratio measurements can provide species-specific isotopic information, which could be used for tracing the origin of environmental pollutants and elucidation of (environmental) speciation. Using on-line hyphenations of separation techniques with multicollector-ICP-MS (MC-ICP-MS) can save time and effort and enables the analysis of different species during a single measurement.
In this work, we developed an on-line hyphenation of CE with multicollector-ICP-MS (CE/MC-ICP-MS) for isotopic analysis of sulfur species using a multiple-injection approach for instrumental mass bias correction by standard-sample bracketing. With this method, the isotopic composition of sulfur in sulfate originating from river water could be analyzed without sample preparation. The results were compared to data from off-line analysis of the same samples to ensure accuracy. The precision of the results of the on-line measurements was promising regarding the differentiation of the river systems by the isotopic signature of river water sulfate. The great potential of this method is based on the versatility of the applied separation technique, not only in the environmental field but also for, e.g., biomolecules, as sulfur is the only covalently bound constituent of proteins that can be analyzed by MC-ICP-MS.
Materials in contact with the environment release e.g., metal-ions, elemental species and/or (nano-)particles. Once these species and/or particles are released, they are ingested by organisms and cells and thus, might have a negative impact on the environment. Thus, identification as well as quantification of potentially harmful substances is of utmost importance and highly needed to assess ecotoxicological impact of (emerging) pollutants.
The oral presentation provides an overview on the power of elemental analytical techniques, in particular: ICP-MS as well as HR-CS-GFMAS in environmental research. Current research topics will be highlighted:
i) Elemental Speciation analysis of anti-fouling agents via CE/MC-ICP-MS;
ii) Per- and polyfluorinated compounds in surface waters via high resolution-continuum source-graphite furnace molecular absorption spectroscopy (HR-CS-GFMAS);
iii) Single cell and single organism analysis via sc-ICP-ToF-MS and ETV/ICP-MS for ecotoxicological assessment.
The introduction of fluorine in organic molecules leads to new chemical/physical properties and up to now more than 6000 fluorinated substances are on the market. Especially in the field of pharmaceuticals, fluorinated organic molecules are becoming more and more popular and at present amount up to 25% of market share, with an upward trend. Highly fluorinated organic substances are also used in technical applications (e.g., coatings, fire-extinguishing agents, textiles). However, next to beneficial aspects of per- and polyfluorinated compounds (PFAS) these substances belong to the class of “emerging contaminants” in particular due to their high persistence and ubiquitous presence in the environment. Due to the large variety of fluorinated substances and increasing production volumes, it is most likely that numerous and up to date unknown fluorine-species are present in the (aquatic) environment. Sum parameter analytical methods to assess the degree of contamination of surface waters with organically bound fluorine are highly needed.
Within this presentation the development of a high resolution-continuum source-graphite furnace molecular absorption spectrometry (HR-CS-GFMAS) method for PFAS analysis is presented. Fluorine detection is enabled upon the addition of a molecule forming agent – Ga turned out being the most sensitive one. Furthermore, the injection as well as temperature program was optimized, and appropriate solid phase extraction (SPE) phases were identified for PFAS extraction. Our developed HR-CS-GFMAS method turned out as a versatile tool in PFAS analysis in a broad variety of matrices – some recent applications will be highlighted as well.
Materials are key for our modern communities; current life seems nearly impossible without concrete, plastic and metal. In particular metals play important roles in all areas of our daily life - from building materials to high tech products.
However, due to the increasing consumption of metals and corresponding waste production, an elevated release of metals from buildings and consumer goods into the environment takes place. Furthermore, metals in direct contact with the environment undergo corrosion processes which leads also to a release of metals into the (aquatic) environment. Besides this immediate metal release, the lifespan of products/buildings are substantially reduced – hence unnecessary economic costs arise. Thus, research in this regard is needed within the force field of metal/material environment.
However, to evaluate the environmental impact of materials as well as developing “safe” materials, new analytical methods are highly needed. One promising powerful tool in this regard is single cell-ICP-ToF-MS for multi-elemental analysis on a single cell/organism level.
Within this presentation the concept, strength as well as challenge of single cell-ICP-MS are briefly introduced. Afterwards, two application examples are presented: (i) assessing the environmental impact of metals and (ii) the impact of the environment on metal-based materials and the derivation of potential environmental-friendly material protection strategies. These applications highlight the strength of new analytical approaches to explore the durability and safety of newly developed materials. Thus, analytical chemistry is one corner stone to transformation of modern society into circular economy (CEco).
(i) Diatoms are located at the bottom of the food chain. Thus, toxicological relevant metals taken up by diatoms can possibly accumulate within the food web and cause harmful effects. Diatoms are a common test system in ecotoxicology. To investigate potential metal uptake and harmful effects on a single cell level, we developed an on-line single cell-ICP-ToF-MS approach for multi-elemental diatom analysis. Our approach is a new potential tool in ecotoxicological testing for metal-based materials.
(ii) Next to classical corrosion processes, microorganisms are responsible for so called microbially influenced corrosion (MIC). MIC is a highly unpredictable process relying on the interaction pathways between cells and the metal surface. To shed light on MIC processes and derivate potential metal protection strategies, we applied single cell-ICP-ToF-MS for MIC research on a single bacteria/archaea level. It turned out that microorganism are taking up particular metals from alloys - thus, single bacteria-ICP-ToF-MS will enable the development of environmental friendly corrosion protection strategies.
Diatoms are located at the bottom of the food chain. Toxicological relevant metals can possibly accumulate within the food web and cause harmful effects. Diatoms are a test system in ecotoxicology. Toxicological effects weaken the growth of algae which is by default investigated by means of fluorescence detection. On basis of the expose concentration as well as obtained fluorescence data potential threshold exceedance in e.g. surface waters is assessed.
However, this approach does not allow for the determination of “real” accumulated metal concentration in diatoms. Common approaches are based on bulk analysis via e.g. ICP-MS, ICP-OES or AAS. But, biological variability is completely disregarded.
To tackle this problem, alternative approaches are highly needed. Within the last years, sp-ICP-MS for nanoparticle as well as single cell analysis turned out as a powerful technique to analyze metal contents as well as size distributions on broad size range. But, common ICP-MS systems do not allow for multi-element detection within single particle/cell events. Thus, simultaneous MS detection devices are needed - just recently, ICP-ToF-MS experienced a revival.
Within our previous work, we developed an automated sample introduction system based on a HPLC system on-line with single particle-ICP-MS, which allowed for ionic background separation and single algae analysis. However, for unambiguous tracing several fingerprint elements and multielement analysis in single algae (diatoms) is needed. Thus, we coupled our previous setup on-line to ICP-ToF-MS. Test diatom species were exposed to test substances (Zn) as well as nanoparticles (FeNPs).
The developed setup allowed for a fast, automated and multielement analysis in single diatoms. Furthermore, we combined our approach with multivariate data assessment - multielement detection of characteristic fingerprint elements allowed for an unambiguous diatom tracing. Clustering of diatoms according to metal exposure concentration levels was enabled. Our approach is a new potential tool in ecotoxicological testing.
In den vergangen Jahren hat das Umweltbewusstsein in der Bevölkerung stark zugenommen und somit auch das Interesse an der Vermeidung von anthropogenen (Schad-)Stoffen in der Umwelt. Eine (neue) Substanzklasse, deren Umweltauswirkungen noch nicht vollständig untersucht sind und die in den vergangenen Jahren immer mehr an Bedeutung gewonnen hat, sind (metallbasierte) Nanomaterialien. Im Gegensatz zu bspw. Elementspezies weisen Nanomaterialien eine Vielzahl von Eigenschaften auf und lassen sich nicht über nur ein Merkmal beschreiben - dies stellt eine große analytische Herausforderung dar. Hier haben sich vor allem die Feld-Fluss-Fraktionierung (AF4) und die single-particle-ICP-MS als leistungsstarke analytische Methoden herausgestellt. In (aquatischen) Umweltmatrizes (z.B. Oberflächengewässern) liegen neben artifiziellen auch natürliche Partikel vor, was eine weitere große Herausforderung für den Nachweis von Nanomaterialien darstellt.
Neben dem Nachweis von anthropogenen Stoffen in der Umwelt ist zudem deren ökotoxikologische Bewertung wichtig. In der aquatischen Ökotoxikologie werden hierzu Testorganismen mit den jeweiligen Substanzen über die Wasserphase exponiert. Effektkonzentrationen (EC50) werden dabei auf Basis der Konzentrationen in der Wasserphase abgeleitet - tatsächlich bioakkumulierte Mengen werden hierbei jedoch meist nicht ermittelt; eine weitere große Herausforderung besteht zudem in der Bewertung von Mischungstoxizitäten. Gängige Testorganismen sind u.a. Kieselalgen (Diatomeen). Diatomeen stehen am Anfang der Nahrungskette - toxikologisch relevante Metalle/Nanomaterialien können sich hierüber im Nahrungsnetz der Oberflächengewässer anreichern und ggf. nachhaltig auswirken.
Im ersten Teil des Vortrages werden zunächst neue elementanalytische Methoden zum Nachweis von metallbasierten Nanopartikeln in Umweltmatrizes auf Basis der AF4/ICP-SFMS sowie stabilen Isotopenlabeln am Beispiel von Eisennanopartikeln vorgestellt.
Im zweiten Teil wird eine neue elementanalytische Methode als komplementäre Technik zur ökotoxikologischen Bewertung von (Schad-)Stoffen vorgestellt. Die neue Methode basiert auf der on-line Kopplung von HPLC mit der single-cell-ICP-(ToF)-MS (sc-ICP-(ToF)-MS) [1, 3-5]. Hierüber konnten wir erfolgreich die automatisierte Multielementanalytik einzelner Diatomeen realisieren und zur Analyse von mit Metallen inkubierten Diatomeen (cyclotella meneghiniana) einsetzen. Wir konnten zeigen, dass die sc-ICP-ToF-MS zukünftig eine leistungsstarke, komplementäre Technik in der aquatischen Ökotoxikologie zum z.B. Test von Metallen und Nanomaterialien darstellt.
Analysis of single cells via LA-ICP-MS is a technique with great potential, however manual targeting of single cells is laborious and therefore microarraying of cells looks promising. In this work, we investigate the potential of a commercial non-contact piezo dispenser arraying system (S3, Scienion AG, Berlin), equipped with a novel technology for single-cell isolation called CellenONE™ (Cellenion, Lyon). Usually if one aims to create a microarray of single cells via spotting a suitably diluted cell suspension, one will observe a Poisson-distributed cell number per spot. CellenONE™ overcomes this problem by controlling the number of cells optically in the piezo dispense capillary (PDC) via image recognition to obtain true single cell arrays. The figures of merit of the customized and optimized setup will be presented. In a proof of concept experiment we investigated the trace elemental fingerprint of THP-1 cells by LA-ICP-TOF-MS (Analyte G2, Teledyne Cetac; icpTOF, TOFWERK) and quantified two metal cell dyes, mDOTA-Ho (CheMatech, Dijon), and Ir-DNA intercalator (Fluidigm, San Francisco). For that, matrix matched calibration standards after Wang et al. were successfully prepared using the same arraying system. We believe that this novel approach opens new ways for automated quantitative single cell LA-ICP-MS.
Inductively coupled plasma mass spectrometry (ICP-MS) is a powerful method for the matrix-independent quantitative analysis of target elements. Developed for the use in inorganic trace analysis, ICP-MS is nowadays a valuable tool for bioanalytical questions. Especially the use of ICP-MS for quantitative proteomics by measuring heteroatoms has gained recognition in the last decade, considering that established quantification methods like organic mass spectrometry depend on labelling of the target protein or the existence of matched protein and peptide standards. The need for reliable quantification of proteins is continuously growing, but only a limited number of well-characterized and quantified protein standards are available so far. Accurately quantified, traceable protein standards are necessary to ensure comparability of measurements between laboratories, not only in basic research but also in a clinical context. One example of this is the Alzheimer’s disease biomarker tau protein. However, existing tau standards lack comparability, emphasizing the need for a well-quantified protein standard.
Therefore, we developed a method for the quantification of pure proteins via sulfur isotope dilution ICP-MS (IDMS). As sulfur is present in two amino acids, cysteine and methionine, it exists in nearly all proteins and can be used for the quantification of proteins of known stoichiometry. We employed simple offline strategies for the separation of non-protein bound sulfur species. Quantification of these contaminations by IDMS allows for correction of the protein content and enables reliable protein quantification. We report the protein mass fractions of a standard reference material and commercially available proteins determined by sulfur IDMS, including the expanded uncertainties. The developed method can be applied for the reliable and traceable quantification of pure proteins for use as in-house standards. Here, we successfully used this method for the quantification of the tau protein.
Neurodegenerative diseases are one of the major problems for our ageing society. Alzheimer’s disease (AD) as the most common neurodegenerative disorder affects over 46.8 million people worldwide and the number will increase as the population ages. The diagnosis of AD is challenging and only half of the patients are identified yet and often only in late stages. One reason is that existing assays for identification and quantification of AD biomarkers lack accuracy and are poorly comparable.
This study is part of the EU project “ReMiND” aiming to develop accurate, reliable and traceable methods for the detection and quantification of known and suspected AD biomarkers. Our target is the tau protein, as brain load and distribution of tau is highly correlated with the clinical progression of AD. We intend to develop a measurement method for the accurate quantification of tau by means of inductively coupled plasma mass spectrometry (ICP-MS).
ICP-MS is a powerful method for the matrix independent quantitative analysis of target elements. Developed for the use in inorganic trace analysis, ICP-MS is nowadays emerging as a valuable tool for bioanalytical questions. Especially the use of ICP-MS for quantitative proteomics by measuring heteroatoms is highly promising, considering that established quantification methods like organic mass spectrometry depend on the existence of matched protein and peptide standards or labelling of the target protein. In this work, we applied isotope dilution analysis (IDA) using ICP-MS to quantify proteins of known stoichiometry via their sulphur content. Sulphur is present in two amino acids, cysteine and methionine, and hence is omnipresent in nearly all proteins. A NIST standard bovine serum albumin (BSA) was quantified using sulfur IDA to optimize sample preparation and method parameters. Our goal is to employ the developed method in a proof of concept study for the quantification of the AD biomarker tau extracted from brains of a mouse model for AD.
Inductively coupled plasma mass spectrometry (ICP-MS) is a powerful method for the matrix-independent quantitative analysis of target elements. Developed for the use in inorganic trace analysis, ICP-MS is nowadays emerging as a valuable tool for bioanalytical questions. Especially the use of ICP-MS for quantitative proteomics by measuring heteroatoms has gained popularity in the last decade, considering that established quantification methods like organic mass spectrometry depend on the existence of matched protein and peptide standards or labelling of the target protein. The need for reliable quantification of proteins is constantly growing, but only a limited number of well characterized and quantified protein standards are available so far. Not only in basic research, but also in a clinical context, accurately quantified, traceable protein standards are needed to ensure comparability of measurements between laboratories. One disease with a major impact on our ageing society is Alzheimer’s disease (AD), which is still challenging to diagnose. As this is also due to a lack in comparability and accuracy of existing biomarker assays, the community would greatly benefit from well quantified protein biomarker standards.
In this work, we applied isotope dilution analysis (IDA) using ICP-MS to quantify proteins of known stoichiometry via their sulfur content. Sulfur is present in two amino acids, cysteine and methionine, and hence exists in nearly all proteins. Simple strategies were employed for the detection of low molecular sulfur species to correct for sulfur contaminants and allow for reliable quantification of various proteins. We report the protein mass fractions with expanded uncertainties of a standard reference material and commercially available proteins determined by sulfur IDA. The herein developed method can be applied for the reliable and traceable quantification of pure proteins and will be used for the quantification of an AD biomarker. Our target is the tau protein, as brain load and distribution of tau is highly correlated with the clinical progression of AD.
PFAS (Per- and polyfluoroalkyl substances) are a widespread and emerging environmental problem due to their longevity and ubiquitous spread. The common structural motif of this compound class is the fluorine – carbon bond on an alkyl backbone, which are known for their chemical inertness and combination of hydrophobicity and oleophobicity. The downside of those properties is the general lack of usable molecular interactions for adsorption to extract them from the environment. The notable exception to that inertness are fluorine – fluorine interactions, which are stronger, the longer the perfluorinated chain length is. Therefore, in this project we investigated the effect of fluorination, length and presence of a charge on the alkyl chain on an adsorber. Towards that goal, in total 16 different adsorber materials were synthesized (fluorinated/non-fluorinated; C4/ C6/ C8/ C10 ; positive charge/no charge) and tested in regard to their potential to adsorb PFOA and perfluoralkylic acids of differing chain lengths. The PFAS concentration was tested via LC-MS/MS to determine the adsorption rate on the various materials. Further work includes the transition from a target analytics to sum parameter analysis for future evaluation of adsorber materials in PFAS environmental samples like river samples. Therefore a quarterly sampling and extraction of spree surface water samples was planned.
Heritage Lecture
(2018)
After finishing my diploma thesis in plasma physics in 1981, I dreamt of a future in a research lab to develop novel fusion reactors for energy production or to study universal plasmas and their emission in the cosmos. This dream never became real, however I found my first job in a team to build up a new museum dedicated to “Energy”, and this first part of my career was already finished after a year, because the funding was not extended. So, I found immediately a new job as a young scientist in the institute for analytical sciences (originally ISAS: Institute for Plasmachemistry and Applied Spectroscopy) in 1982 to develop novel plasma ion sources for inorganic mass spectrometry. The first source of interest was based on a glow discharge for direct analysis of conducting solids (technically supported by Finnigan MAT, Bremen). Here I adopted the design of the Grimm type discharge for the first time, which was well known in optical emission spectroscopy, and coupled it to a quadrupole mass analyzer. The advantage of this design was that flat craters are produced by sputtering which made this source very powerful for in-depth analysis of technical layers. This then became the topic of my PhD, which was not originally planned, and I had to learn a lot about surface analysis. However, since the first project was too successful we established a small team (in cooperation with Jose Broekaert - an expert in ICP-OES) which started with the development of our own inductively coupled plasma ion source in 1986 coupled to a quadrupole and in 1989 to a sector field mass spectrometer (funded by the Minister of Science and Technology; again in cooperation with Finnigan MAT). The latter device was launched to the market in 1993 as the Element 1.
The second decade of my career was still related to instrumental development but mainly of glow discharge sources. In an EU funded project first an automated glow discharge sector field instrument was developed where the Grimm type geometry was combined with a fast flow concept (in cooperation with Volker Hoffmann at IFW in Dresden). This was done in cooperation with VG (which became later a part of Thermo Fisher Scientific together with Finnigan MAT), so that it is not surprising that this concept for the Element GD. This project was later continued in the third phase of my career, again funded by the EU and in cooperation with the group of Alfredo Sanz-Medel (Rosario Pereiro and Jorge Pisonero), to develop a fast flow, but now rf-powered GD ion source in combination with a time-of-flight mass spectrometer, which was later launched to the market commercially by Horiba Jobin Yvon (France) for in-depth profiling of thin layers even of non-conducting materials.
In the first decade of my career I started to study already “analytical chemistry” from the scratch because the instruments developed have been applied now for direct analysis of solid materials, technical layers and environmental samples. In case of environmental applications our ICP-MS (the quadrupole and the sector field instrument) was coupled with separation techniques, so that this period of instrumental development was dominated in the second decade by development of high efficiency sample introduction systems in combination with speciation studies of Pt group elements, arsenic, selenium and phosphorus (in DNA and phosphorylated proteins), Ni and Cr. Additionally, we continued with the analysis of solid ceramic materials (Al2O3, SiC, SiN) and ambient air-born particles. At the end of the second decade we complemented our instrumental pool by a collision and reaction cell instrument in cooperation with Micromass and used this instrument for speciation studies of peptides and proteins and demonstrated that by ICP-HEX-MS quantitative proteomics is feasible. Therefore, we more and more focused in the following years on metalloproteins and published a famous paper on “Metallobiomolecules: The basis of life, the challenge of atomic spectroscopy” (together with Luc Moens and Ryszard Lobinski). For detection of metalloproteins we applied typical workflows of biochemistry and proteomics, for which I had to extend my knowledge about biochemistry and proteomics. As a new analytical tool, we used a homemade laser ablation cell for sample introduction of metalloproteins after their separation by gel electrophoresis and extended this work by applying metal-tagging of antibodies for Western blot assays. For this purpose, proteins were separated in SDS-PAGE and electroblotted onto membranes. Specific detection of proteins even not containing any metal could be performed by laser ablation ICP-MS using the metal tagged antibodies for indirect detection. This research was interrupted in 2009 by a movement from ISAS (where atomic spectroscopy was declining) to BAM (the Federal Institute for Materials Research and Testing, Berlin) where this research direction was fostered. The experience we achieved at ISAS in the previously mentioned projects were now used here at BAM in the fourth decade for materials research and the development of a quantitative elemental microscope with cellular resolution. So, at the end of my career I am trying to apply all my knowledge and expertise to develop analytical methods and to apply multimodal spectroscopies to decipher the construction code of the cellular machinery, which is the most precise and complex machinery I have ever seen. If we were able to understand how this machinery works, we can better diagnose and treat a malfunction in case of the development of a disease.
Finally, I can conclude that lifelong learning starts before school but does not end at the end of this lecture. It looks like this heritage lecture will be focused on my career only, but this is not the case because some highlights of my career will be used to illustrate a few universal principles: how to have fun, how to find friends and how this all leads to an increase of joy and joy is the basis of new ideas (which must not always be related to your profession) and novel ideas are essential for a successful and satisfying career. So, this heritage lecture wants to answer the most important question of a life which was dedicated to plasma spectrochemistry:
1) Is it possible - at all - to have fun in this research direction?
2) Can we learn already today what we need tomorrow?
3) How can we still realize our scientific dreams of cutting edge research in times of cutting budgets? Which automatically leads to the next question:
4) Is necessity the mother of invention?
All questions will be answered! Controversial discussions (for angry or disappointed colleagues) will be stimulated and my visions of future research (for students and postdocs) and instrumental developments (for manufacturer) will be presented. Finally, conclusions will be drawn by the auditorium (everybody) and thanks will be given to Ramon Barnes (by me) already in advance!
Heritage Lecture
(2018)
After finishing my diploma thesis in plasma physics in 1981, I dreamt of a future in a research lab to develop novel fusion reactors for energy production or to study universal plasmas and their emission in the cosmos. This dream never became real, however I found my first job in a team to build up a new museum dedicated to “Energy”, and this first part of my career was already finished after a year, because the funding was not extended. So, I found immediately a new job as a young scientist in the institute for analytical sciences (originally ISAS: Institute for Plasmachemistry and Applied Spectroscopy) in 1982 to develop novel plasma ion sources for inorganic mass spectrometry. The first source of interest was based on a glow discharge for direct analysis of conducting solids (technically supported by Finnigan MAT, Bremen). Here I adopted the design of the Grimm type discharge for the first time, which was well known in optical emission spectroscopy, and coupled it to a quadrupole mass analyzer. The advantage of this design was that flat craters are produced by sputtering which made this source very powerful for in-depth analysis of technical layers. This then became the topic of my PhD, which was not originally planned, and I had to learn a lot about surface analysis. However, since the first project was too successful we established a small team (in cooperation with Jose Broekaert - an expert in ICP-OES) which started with the development of our own inductively coupled plasma ion source in 1986 coupled to a quadrupole and in 1989 to a sector field mass spectrometer (funded by the Minister of Science and Technology; again in cooperation with Finnigan MAT). The latter device was launched to the market in 1993 as the Element 1.
The second decade of my career was still related to instrumental development but mainly of glow discharge sources. In an EU funded project first an automated glow discharge sector field instrument was developed where the Grimm type geometry was combined with a fast flow concept (in cooperation with Volker Hoffmann at IFW in Dresden). This was done in cooperation with VG (which became later a part of Thermo Fisher Scientific together with Finnigan MAT), so that it is not surprising that this concept for the Element GD. This project was later continued in the third phase of my career, again funded by the EU and in cooperation with the group of Alfredo Sanz-Medel (Rosario Pereiro and Jorge Pisonero), to develop a fast flow, but now rf-powered GD ion source in combination with a time-of-flight mass spectrometer, which was later launched to the market commercially by Horiba Jobin Yvon (France) for in-depth profiling of thin layers even of non-conducting materials.
In the first decade of my career I started to study already “analytical chemistry” from the scratch because the instruments developed have been applied now for direct analysis of solid materials, technical layers and environmental samples. In case of environmental applications our ICP-MS (the quadrupole and the sector field instrument) was coupled with separation techniques, so that this period of instrumental development was dominated in the second decade by development of high efficiency sample introduction systems in combination with speciation studies of Pt group elements, arsenic, selenium and phosphorus (in DNA and phosphorylated proteins), Ni and Cr. Additionally, we continued with the analysis of solid ceramic materials (Al2O3, SiC, SiN) and ambient air-born particles. At the end of the second decade we complemented our instrumental pool by a collision and reaction cell instrument in cooperation with Micromass and used this instrument for speciation studies of peptides and proteins and demonstrated that by ICP-HEX-MS quantitative proteomics is feasible. Therefore, we more and more focused in the following years on metalloproteins and published a famous paper on “Metallobiomolecules: The basis of life, the challenge of atomic spectroscopy” (together with Luc Moens and Ryszard Lobinski). For detection of metalloproteins we applied typical workflows of biochemistry and proteomics, for which I had to extend my knowledge about biochemistry and proteomics. As a new analytical tool, we used a homemade laser ablation cell for sample introduction of metalloproteins after their separation by gel electrophoresis and extended this work by applying metal-tagging of antibodies for Western blot assays. For this purpose, proteins were separated in SDS-PAGE and electroblotted onto membranes. Specific detection of proteins even not containing any metal could be performed by laser ablation ICP-MS using the metal tagged antibodies for indirect detection. This research was interrupted in 2009 by a movement from ISAS (where atomic spectroscopy was declining) to BAM (the Federal Institute for Materials Research and Testing, Berlin) where this research direction was fostered. The experience we achieved at ISAS in the previously mentioned projects were now used here at BAM in the fourth decade for materials research and the development of a quantitative elemental microscope with cellular resolution. So, at the end of my career I am trying to apply all my knowledge and expertise to develop analytical methods and to apply multimodal spectroscopies to decipher the construction code of the cellular machinery, which is the most precise and complex machinery I have ever seen. If we were able to understand how this machinery works, we can better diagnose and treat a malfunction in case of the development of a disease.
Finally, I can conclude that lifelong learning starts before school but does not end at the end of this lecture. It looks like this heritage lecture will be focused on my career only, but this is not the case because some highlights of my career will be used to illustrate a few universal principles: how to have fun, how to find friends and how this all leads to an increase of joy and joy is the basis of new ideas (which must not always be related to your profession) and novel ideas are essential for a successful and satisfying career. So, this heritage lecture wants to answer the most important question of a life which was dedicated to plasma spectrochemistry:
1) Is it possible - at all - to have fun in this research direction?
2) Can we learn already today what we need tomorrow?
3) How can we still realize our scientific dreams of cutting edge research in times of cutting budgets? Which automatically leads to the next question:
4) Is necessity the mother of invention?
All questions will be answered! Controversial discussions (for angry or disappointed colleagues) will be stimulated and my visions of future research (for students and postdocs) and instrumental developments (for manufacturer) will be presented. Finally, conclusions will be drawn by the auditorium (everybody) and thanks will be given to Ramon Barnes (by me) already in advance!