Chemische Charakterisierung und Spurenanalytik
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Enhancing efficiency at bamline: employing data science and machine learning for x-ray research
(2023)
This talk discusses how data science and machine learning techniques are being applied at the BAM Federal Institute for Materials Research and Testing to enhance efficiency and automation at the BAMLine synchrotron facility. The methods presented include Gaussian processes and Bayesian optimization for beamline adjustment and optimization of X-ray measurements. These statistical techniques allow automated alignment of beamline components and active learning scanning to reduce measurement time.
Additional machine learning methods covered are neural networks for quantification of X-ray fluorescence (XRF) data and decoding coded apertures.
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.
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.
Parkinson’s disease (PD) is one of the most common neurodegenerative disorders worldwide. About 0.3 % of the global population and approximately 2 % of people older than 80 years are affected by PD. Monoamine oxidase B (Mao B) is an enzyme, which is a drug target in Parkinson’s disease (PD), since it is involved in dopamine metabolism. Several Mao B inhibitors are well established as medication for PD patients. However, the medical treatment is only little personalized since the monitoring of the patients Mao B activity is complex and requires sophisticated laboratory equipment. Here a sensorial Mao B activity determination system has been developed which has potential in the personalization of the medical PD treatment. The enzyme activity is quantified by amperometric detection of enzymatically produced H2O2. Therefore, the enzyme is enriched from the solution via cellulose particles which are functionalized with antibodies against human Mao B. The successful capturing of the enzyme can be verified by SDS-PAGE. For activity determination the enzyme is brought in contact with a suitable substrate - here benzylamine. Selectivity of the amperometric hydrogen peroxide detection in the presence of co-reactants has been verified. Within the time span of 30 min, a linear dependency of enzymatically produced H2O2 with the substrate incubation time can be observed. This allows the evaluation of the Mao B activity. The results have been correlated to an optical detection method. Furthermore, the method has been tested for different amounts of enzyme used in the experiments and found to be sensitive enough for Mao B analysis in blood samples.
High purity halides of III-VI group elements, especially chloride and fluorides, are used in gas phase technologies for obtaining high purity materials and coatings. The reduction of halides in hydrogen-halide mixtures can be achieved in various discharge plasmas, e.g. inductively coupled, ark, and even laser-induced plasmas. Existing models of such plasmas are not sufficiently accurate to predict a yield of the targeted compounds and to describe the plasma processes involved in formation of these compounds. Besides, a construction of costly plasma-chemical reactors can be alleviated by the prior modeling of plasma processes that may occur in such reactors.
A goal of this work is to extend the model, which was initially developed for laser induced Plasmas, to plasmas used in chemical reactors, in particular, the inductively-coupled-RF discharge Plasma. The model predicts equilibrium chemical compositions of reaction mixtures as functions of plasma temperature and stoichiometry of reactants. The mixtures investigated are BCl3/H2/Ar and BF3/H2/Ar where Ar serves as the plasma-forming gas and H2 as a binding agent which binds the active species Cl and F and Cl- and F-containing intermediates to produce gaseous B and its condensate. An additional goal is to obtain information about intermediate reaction products for different ratios of BCl3/H2 and BF3/H2 and at different temperatures and different Ar flow rates.
It is found that the desired components B and B2 appear at appreciable concentrations of >0.1% and ~0.01% respectively only at temperatures above 3000 K. It is also established that the effect of charged species on the reaction products is miniscule for temperatures below 5000 K. The expected yield of boron as a function of the original mole fraction H2/BCl3 and H2/BF3 is calculated. The mole fractions are varied in the range 0.1-1000 and the temperature in the range 1000-10000 K. It is shown that the yield of boron increases with increasing the molar ratio H2/BCl3 and H2/BF3 up to ~100 in the temperature range 2000-5000 K. At higher temperatures, T>5000 K, the boron concentration reaches its maximum and does not depend on the concentration of hydrogen; all molecules dissociate and chemical reactions proceed only between charged particles (mostly elemental ions) and electrons. The calculated plasma parameters and composition are compared with experimental data obtained by optical emission spectroscopy. The calculated plasma temperature and electron density are shown to be in good agreement with the measured ones.
In der Verbindungsklasse der per- und polyfluorierte alkylischen Substanzen (PFAS) werden über 5200 organische Verbindungen zusammengefasst. PFAS sind an mindestens einem Kohlenstoffatom vollständig fluoriert. Sie werden mit negativen Einflüssen auf die menschliche und tierische Gesundheit assoziiert, sind extrem persistent in der Umwelt und bioakkumulieren entlang von Nahrungsnetzen. Daher zählen PFAS zu den „emerging pollutants“. Gleichzeitig machen ihre physikalisch-chemischen Eigenschaften sie für die Verwendung in diversen technischen Anwendungen attraktiv. Sie sind sowohl hydro- als auch lipophob und zeigen durch die starke C-F-Bindung hohe thermische wie chemische Beständigkeit.
Erste Regulierungen einiger PFAS in Kombination mit den technisch hervorragenden Eigenschaften erzeugt einen Innovationsdruck und führten zu einem enormen Anstieg in der Zahl der Substitutionsverbindungen. Auf Grund der steigenden Komplexität der Substanzklasse ist die Target-Analytik nicht in der Lage eine solche Vielfalt und Vielzahl an Analyten zu erfassen.
Für eine akkurate Erfassung der Belastungssituation durch PFAS, die Identifikation von PFAS-Hotspots und eine Bewertung von geeigneten Sanierungsmaßnahmen ist daher eine geeignete PFAS-Summenparameteranalytik notwendig.
Daher geben wir hier Einblicke in den aktuellen Stand der PFAS-Summenparameterentwicklung und präsentieren unsere neusten Ergebnisse zur Methodenentwicklung für die quantitative Analyse von PFAS als extrahierbares organisch gebundenes Fluor (EOF) in Umweltproben mittels hochauflösender Molekülabsorptionsspektrometrie (HR-CS-GFMAS). Hierfür optimierten wir die Extraktion von PFAS aus verschieden Feststoff-Matrizes bei zeitgleicher Abtrennung anorganischen Fluorids. Durch den Zusatz von Galliumsalz-Lösungen als modifier in der HR-CS-GFMAS kann Fluor indirekt sehr selektiv durch die in situ Bildung von GaF sehr nachweisstark (instrumentelle LOQ ~3 µg/L) quantifiziert werden.
Im der Präsentation werden, neben der Möglichkeit der Mikroplastikquantifizierung, auf weitere Anwendungsfelder der Methode TED-GC/MS eigegangen. Dies beinhaltet die Erfassung von Degradationsprodukten UV/O2 geschädigter Polymere und die Detektion von Additiven. Die Optimierung der Methode betreffend Messzeit und materialspezifischer Messanforderung sind ebenfalls Gegenstand.
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.
Fast quantitative detection of microplastics using TED-GC/MS, an innovative thermoanalytical method
(2021)
In the talk, the BAM is introduced and the motivation for our engagement in the field of microplastic analysis is explained. The challenges in the analysis of microplastics are shown and how we deal with them. The working principle of TED-GC/MS and its performance parameters are presented, as well as the procedure for identifying and quantifying polymers in environmental samples. Interesting results are shown using selected examples. Finally, BAM's microplastic reference materials are highlighted.
Since it is unknown for many applications, which PFASs are used and how they enter the environment, target analysis-based methods reach their limits. The two most frequently used sum parameters are the adsorbable organically bound fluorine (AOF) and the extractable organically bound fluorine (EOF). Both can be quantified using either combustion ion chromatography (CIC) or high resolution-continuum source-graphite furnace molecular absorption spectrometry (HR-CS-GFMAS). Here we provide an insight on the advantageous and disadvantageous of both sum parameters and both detection methods. Our study is based on the analysis of surface water samples. Next to total fluorine (TF) analysis, AOF and EOF were determined as well as CIC and HR-CS-GFMAS are compared and results are comparatively discussed. Fluorine mass balancing revealed that, the AOF/TF proportion was higher than the EOF/TF proportion. The AOF made up 0.14–0.81% of TF and the EOF 0.04–0.28% of TF. Although, organically bound fluorine represents only a small portion of TF, PFASs are of worldwide concern, because of their extreme persistence and their bioaccumulation potential. The EOF-HR-CS-GFMAS method turned out to be more precise and sensitive than the AOF-CIC method and is a promising tool for future monitoring studies/routine analysis of PFASs in the environment.
Contamination of natural bodies of water with oil and lubricants (or generally, hydrocarbon derivatives such as petrol, fuel and others) is a commonly found phenomenon around the world due to the extensive production, transfer and use of fossil fuels. The timely identification of these contaminants is of utmost importance, since they directly affect water quality and represent a risk for wildlife and human health even in trace amounts.
In this work, we develop a simple system for the on-field detection of total petroleum hydrocarbons (TPH) in water and soil, the "Spectrocube". The test is based on the measurement of the fluorescence signal emitted by the molecular rotor 4-DNS-OH dye. This dye is embedded in a hydrophobic polymeric matrix (PVDF), avoiding interactions of water with the dye and providing a robust support for use in test-strip fashion. The test-strip’s fluorescence intensity increases linearly at low concentrations of TPH, reaching a saturation value at higher concentrations.
For excitation and evaluation of the test-strip fluorescence, a simple miniature optical system was designed. The system works semi-quantitatively as solvent-free TPH detection kit, as well as quantitatively when using a simple cyclopentane extraction step. To simplify the fluorescence read-out, the device is coupled to a tablet computer via Bluetooth, running a self-programmed software ("app").
Following fluorinated drugs by molecular absorption spectrometry – from cancer cells to body fluids
(2018)
Fluorine has been widely introduced into pharmaceutical drugs. Due to the high C-F bond strength, a single atom substitution with fluorine produces drastic desirable and tunable changes in the molecular properties. However, the clinical monitoring of these drugs is not straightforward.
Organofluorine compounds are elusive for a non-targeted analysis; a significant problem in fluorine determination is the lack of suitable detection techniques. Standard atomic absorption and emission spectrometers cannot access fluorine, because their resonance lines lie in the VUV spectral range below 100 nm. In the case of conventional inductively coupled argon plasmas (ICP), the plasma energy is too low to generate a significant population of excited fluorine atoms. Recently, our group introduces high-resolution continuum source absorption spectrometry (HR-CS MAS) as a new way for the indirect monitoring of fluorinated compounds. Main benefits of HR-CS-MAS includes low limits of detection, complete analyte recovery, simple to no sample preparation, and short time analysis.
Formaldehyde is considered as carcinogenic and is emitted from particleboards and plywood used in toy manufacturing. Currently, the flask method is frequently used in Europe for market surveillance purposes to assess formaldehyde release from toys, but its concordance to levels measured in emission test chambers is poor. Surveillance laboratories are unable to afford laborious and expensive emission chamber testing to comply with a new amendment of the European Toy Directive; they need an alternative method that can provide reliable results. Therefore, the application of miniaturised emission test chambers was tested. Comparisons between a 1 m3 emission test chamber and 44 mL microchambers with two particleboards over 28 days and between a 24 L desiccator chamber and the microchambers with three puzzle samples over 10 days resulted in a correlation coefficient r2 of 0.834 for formaldehyde at steady state. The correlation between the results obtained in microchambers vs. flask showed a high variability over 10 samples (r2: 0.145), thereby demonstrating the error-proneness of the flask method in comparison to methods carried out under ambient parameters. An exposure assessment was also performed for three toy puzzles: indoor formaldehyde concentrations caused by puzzles were not negligible (up to 8 μg/m3), especially when more conservative exposure scenarios were considered.
Formaldehyd gilt als krebserregend und wird von Spanplatten und Sperrholz emittiert, die bei der Spielzeugherstellung verwendet werden. Die Untersuchungsänter benötigen eine wirtschaftliche und zuverlässige Methode. Die Anwendung miniaturisierter Emissionsprüfkammern wurde getestet und mit größeren Emissionsprüfkammern und die Flaschenmethode verglichen. Eine Expositionsabschätzung wird auch vorgestellt.
Gold is one of the seven metals already known in antiquity and was used from time immemorial as a medium of exchange and for the production of jewelry because of its luster and rarity. In addition, it is easy to work and largely resistant to chemical influences. Investigations of gold using synchrotron radiation excited X-ray fluorescence analysis are non-destructive and provide information about the chemical elements present in the sample under investigation. The investigations presented here at BAMline focus on questions such as the origin, manufacturing process, and association of gold findings. The different questions are explained by a number of examples ranging from the Viking treasure from Hiddensee to the Nebra Sky Disk and finds from Egypt. The find from Bernstorf is discussed in detail. A Bayesian treatment of the authenticity is shown.
By automatically recording as much information as possible in automated laboratory setups, reproducibility and traceability of experiments are vastly improved. This presentation shows what such an approach means for the quality of experiments in an X-ray scattering laboratory and an automated synthesis set-up.
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.
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!
High-resolution absorption isotopic spectrometry as a tool for aging studies of Li-ion batteries
(2022)
Lithium (Li) is the key element in the manufacturing of batteries. Isotopic study of Li may help to identify the causes of battery aging due to isotopic fractionation during charge/discharge cycles.
Isotopic ratio determination is based on monitoring the isotopic components of lithium by their spin-orbit coupling and its isotopic shift of about 15 pm for the 22P←22S electronic transition around 670.788 nm. In this work, we propose improvements to our previous work [1] by using a higher-resolution double echelle modular spectrometer (HR-DEMON II) coupled to a continuum source graphite furnace atomic absorption spectrometer (HR-CS-GF-AAS) for the isotopic analysis of Li.
The data analysis was carried out by using a decision-tree-based ensemble machine learning (ML) algorithm (XGBoost). A set of samples with 6Li isotope amount fractions ranging from 0.0004 to 0.99 mol mol-1 was used for the algorithm's training. Subsequently, the procedure was validated by a set of stock chemicals (Li2CO3, LiNO3, LiCl, and LiOH) and a BAM candidate reference material, a cathode material (NMC111). Finally, the ML model was applied to determine the isotope ratio of geological samples, including anorthosite, granite, soil, rhyolite, nepheline syenite, and basalt and battery samples. These samples were measured as digested without any further purification step.
Improvements in the optical resolution resolve the lithium isotopic components of the atomic spectra. In the studied geological samples, were found δ7Li values between -0.5 and 4.5 ‰ with a precision range of 1 to 2 ‰. In addition, the proposed method was validated with multi-collector inductively coupled plasma mass spectrometry (MC-ICP-MS), and these results are comparable and compatible.
An alternative method for lithium isotope amount ratio analysis is proposed by combining atomic absorption spectrometry with spectra data analysis by machine leaning. It is based on the well-known isotope shift of around 15 pm for the electronic transition at wavelength 670.7845 nm which can be measured by a high-resolution continuum source atomic absorption spectrometer (HR-CS-AAS). For isotope amount ratio analysis, a scalable three boosting machine learning algorithm (XGBoost) was employed and calibrated with a set of samples with a 6Li isotope amount fraction ranging from 99% to 6%. The absolute Li isotope amount fractions of these calibration samples were previously measured by multi-collector inductively coupled plasma mass spectrometry (MC-ICP-MS) and used as ab-initio data for the machine learning algorithm. Validation of the machine leaning model was performed with two standard reference materials (LSVEC and IRMM-016). The procedure was employed for the isotope amount ratio determination of a set of stock chemicals (Li2CO3, LiNO3, LiCl, LiOH, and LiF) as well as a BAM candidate LiMNC cathode reference material. Achieved uncertainties are one order of magnitude higher than those obtained by MC-ICP-MS. This precision and accuracy is nonetheless sufficient to resolve natural occurring variations in Lithium isotope ratios. Also, the LiMNC material was analyzed by HR-CS-AAS with and without matrix purification. The results are comparable within statistical error.
Research into new sources for EUV lithography is driving advancements in experimental methods tailored for this short wavelength range. This progress enables the exploration of spectroscopic techniques aimed at monitoring electronic transitions within this energy spectrum. Laser-induced breakdown spectroscopy (LIBS) serves as a rapid tool for elemental analysis, primarily established in the UV-vis range. However, LIBS encounters challenges such as limited repeatability precision and elevated background noise resulting from continuum radiation.
In parallel, laser-induced extreme UV spectroscopy (LIXS) delves into the initial stages of plasma evolution, characterized by the emergence of soft X-ray and extreme UV radiation. The method benefits from a fast timeframe and constrained plasma confinement, leading to better precision. Nevertheless, LIXS encounters convoluted spectra arising from unresolved transition arrays (UTA), particularly pronounced for heavier elements. This complexity renders conventional univariate data analysis impractical, demanding the adoption of a multivariate data analysis approach.
Multiple cathode samples, each coated with varying stoichiometries of lithium nickel manganese cobalt oxide (NMC), were prepared and used for calibration purposes. Through the application of Partial Least Squares (PLS) regression, a robust correlation with an R2 value exceeding 0.97 was achieved. The LIXS technique underwent a comparative evaluation against UV-vis LIBS. Furthermore, a comparison between univariate and multivariate analysis approaches was conducted, incorporating validation through y-randomization to mitigate overfitting risks.
The viability of this approach was confirmed through the testing of an NMC reference material. The results showed metrological compatibility with reference values, underscoring the potential capability of the proposed methodology.
Accelerating chemical process development and manufacturing along with quick adaption to changing customer needs means consequent transformation of former batch to continuous (modular) manufacturing processes. These are justified by an improved process control through smaller volumes, better heat transfer, and faster dynamics of the examined reaction systems.
As an example, for such modular process units we present the design and validation of an integrated nuclear magnetic resonance (NMR) micro mixer tailor‐made for a desired chemical reaction based on computational modelling. The micro mixer represents an integrated modular production unit as an example for the most important class of continuous reactors. The quantitative online NMR sensor represents a smart process analytical field device providing rapid and non‐invasive chemical composition information without need for calibration. We describe the custom design through computational fluid dynamics (CFD) for the demands of the NMR sensor as well as for the given reaction conditions. The system was validated with an esterification reaction as an example for a chemical reaction process.
Systems utilizing such an online NMR analyser benefits through short development and set‐up times based on “modular” spectral models. Such models can simply be built upon pure component NMR spectra within minutes to a few hours (i.e., assignment of the NMR signals to the components) instead of tedious DoE calibrations runs. We present a range of approaches for the automated spectra analysis moving from statistical approach, (i.e., Partial Least Squares Regression) to physically motivated spectral models (i.e., Indirect Hard Modelling and Quantum Mechanical calculations). The approach was validated for typical industrial reactions, such as hydrogenations or lithiations.
Accelerating chemical process development and manufacturing along with quick adaption to changing customer needs means consequent transformation of former batch to continuous (modular) manufacturing processes. These are justified by an improved process control through smaller volumes, better heat transfer, and faster dynamics of the examined reaction systems.
As an example, for such modular process units we present the design and validation of an integrated nuclear magnetic resonance (NMR) micro mixer tailor‐made for a desired chemical reaction based on computational modelling. The micro mixer represents an integrated modular production unit as an example for the most important class of continuous reactors. The quantitative online NMR sensor represents a smart process analytical field device providing rapid and non‐invasive chemical composition information without need for calibration. We describe the custom design through computational fluid dynamics (CFD) for the demands of the NMR sensor as well as for the given reaction conditions. The system was validated with an esterification reaction as an example for a chemical reaction process.
Systems utilizing such an online NMR analyser benefits through short development and set‐up times based on “modular” spectral models. Such models can simply be built upon pure component NMR spectra within minutes to a few hours (i.e., assignment of the NMR signals to the components) instead of tedious DoE calibrations runs. We present a range of approaches for the automated spectra analysis moving from statistical approach, (i.e., Partial Least Squares Regression) to physically motivated spectral models (i.e., Indirect Hard Modelling and Quantum Mechanical calculations). The approach was validated for typical industrial reactions, such as hydrogenations or lithiations.
This work wants to show the benefit of NMR spectroscopy as online analytical technique in industrial applications for improving process understanding and efficiency. Especially development and set‐up times based on “modular” data analysis models will enable new production concepts, which are currently discussed with respect to digitization of process industry.
PANIC is the ideal forum for such discussions in the application of NMR spectroscopy and its data analysis to the everyday problems in process industry.
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.
How to write your thesis
(2019)
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.
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.
Die Untersuchungen sind durch das das DFG Schwerpunktprogramm 1374 für Biodiversitätsforschung motiviert. Anhand des überwachten Abbaus von Totholz soll untersucht werden, welche Auswirkung unterschiedliche Formen und Intensitäten der Landnutzung auf die Biodiversität innerhalb von drei Exploratorien zeigen. Bei den vorangegangenen Studien wurden Nahrungs¬netzte auf organismischer Ebene sowie Klima- und Umgebungsdaten untersucht und die Veränderung des ausgebrachten Totholzes als Masseverlust erfasst. Es wird jedoch erwartet, dass in Anhängigkeit der beteiligten Organismen und Umgebungsparameter verschiedene Mechanismen des Holzabbaus vorliegen, die in unterschiedlichen Abbauraten der Holzkomponenten Lignin, Cellulose und Hemicellulose resultieren. Aus diesem Grund ist die quantitative Untersuchung des Ligningehalts an Hölzern ein wesentlicher Schritt für ein verbessertes Verständnis der Biodiversität in den untersuchten Exploratorien. Um der hohen Probenanzahl, die sich aus der Kontrolle von jeweils 100 Proben (Plots) in den drei Exploratorien für Hölzer aus 13 Baumarten ergibt, gerecht zu werden, wird eine schnelle und effiziente Untersuchungsmethode benötigt. Diese wird derzeit in Form einer NIR-spektroskopischen Bestimmung des Ligningehalts entwickelt. Um basierend auf den NIR Spektren vermahlener Holzproben Lignin und weitere Holzkomponenten korrekt vorherzusagen, muss zunächst basierend auf nasschemischen Analysen ein chemometrisches Modell kalibriert werden. Dazu ist die Charakterisierung von mindestens 20 – 30 Proben, die eine hohe Varianz des Ligningehalts aufweisen, notwendig. Im Vortrag werden erste Untersuchungs¬ergebnisse für die Vorhersage des Ligningehalts von Kiefernhölzern, die für ein Jahr in dem Exploratorium Schorfheide exponiert wurden, vorgestellt. Die anschließende explorative Datenanalyse (PCA) unter Verwendung von insgesamt 28 Variablen zur Beschreibung klimatischer und Umgebungsparameter weist eine Reihe interessanter Korrelationen auf. Demnach ist der Ligningehalt auf der ersten Hauptkomponente (29% erklärte Varianz) positiv mit dem C/N-Verhältnis und negativ mit Landnutzungsindex korreliert. Masseverlust und Temperatur hingegen dominieren die zweite Hauptkomponente (12% erklärte Varianz).
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.
Immunomagnetic ochratoxin a assay with electrochemical 3,3′,5,5′ tetramethylbenzidine detection
(2021)
The demand for miniaturized analytical devices monitoring important parameters in the food and medical industry has increased strongly in the past decades. With fast progress, smart technologies are finding their way into our everyday life. For the future, it is, therefore, a major goal to also link analytical methods with smart technologies to create user-friendly on-site devices. In food industry the monitoring of harmful substances such as dioxins, heavy metals or mycotoxins plays a key role, since the European Commission prescribes legal limits for various food products and beverages[1]. Therefore, companies often have their own laboratories and trained personnel. For one of the most abundant and toxic mycotoxins, Ochratoxin A (OTA) we want to present an electrochemical detection system in which the read-out can be performed with a smartphone connected via Bluetooth to a miniaturized potentiostat. The recognition of OTA is performed with specific antibodies in a competitive assay format. Anti-OTA-antibodies were captured on magnetic beads on which the competitive binding between OTA and an OTA horseradish peroxidase (HRP) tracer was performed. To quantify OTA, the enzymatic reaction of the tracer with 3,3′,5,5′-tetramethylbenzidine (TMB) and H2O2 is employed. Oxidized TMB, which is enzymatically produced by the reduction of H2O2, is quantified by amperometry with screen-printed electrodes in a custom-made flow system. The results of the electrochemical detection method are in good correlation with the photometric detection of TMB. To demonstrate the applicability, we tested our system with OTA-spiked beer and performed the measurement via smartphone.
An improved algorithm for calibration-free laser induced breakdown spectroscopy (CF LIBS) will be presented which includes several novel features in comparison with previously proposed similar algorithms. In particular, it allows using spectral lines with arbitrary optical thickness for the construction of Saha-Boltzmann plots, retrieves the absorption path length (plasma diameter) directly from a spectrum, replaces the Lorentzian line profile function by the Voigt function, and allows for self-absorption correction using pre-calculated and tabulated data rather than approximating functions. The tabulated data embody the solutions of the radiative transfer equation for numerous combinations of optical thicknesses and line widths. The algorithm is thoroughly verified using synthetic spectra.
Introduction to microplastics, definition, relevance, analytical approaches & challenges. TED-GC/MS working principle, features & performance. Optimisation in TED-GC/MS methodology, new validation data. Replacement of Internal Standard, outlook towards upcoming publication and application within EU´s revised drinking water directive.
High-resolution mass spectrometry, either combined with gas or liquid chromatography (GC/LC-HR-MS), is currently the most powerful analytical option for broad nontargeted small molecule analysis. To transform HR-MS raw data from metabolomics or environmental studies into chemically meaningful data, several computational steps are needed, including peak detection, deconvolution of these peaks into compounds and putative identification of compounds using databases. Each of these steps can cause problems and still requires methodological advancements. Computational compound annotation as one of the steps, however, has proven particularly challenging, mainly due to the chemical diversity of organic analytes. In addition, different annotation approaches are needed for the different platforms used in HR-MS screening. We recently introduced InterpretMSSpectrum as an annotation workflow for GC-HR-MS using atmospheric pressure chemical ionization (APCI). InterpretMSSpectrum locates molecular ion, fragment and adduct peaks, calculates their most likely sum formula combination and graphically summarizes results as an annotated mass spectrum. As a complementary approach for LC-HR-MS, we presented findMAIN, which scores MS1 spectra based on explained intensity, mass accuracy and isotope charge agreement of adducts and related electrospray ionization (ESI) products to determine the neutral mass of unknown compounds. Both approaches were validated against large spectral libraries containing more than 600 compounds, for which correct annotation was achieved in over 80% of the cases. Based on the experiences from this validation, we here compare soft-ionization GC/LC-HR-MS regarding “annotatability” of unknown compounds from a computational perspective. As a main advantage for GC-HR-MS, the relatively uniform ionization behavior of commonly used trimethylsilyl (TMS) derivatives observed under APCI allowed differentiation of molecular ion peaks from in-source fragments based on relatively compact set of rules. By contrast, neutral mass inference in ESI required a more complex evaluation scheme, due to the higher diversity of ionization products observable in ESI. We demonstrate such differences by practical examples of both software packages applied to metabolomics studies and discuss the challenges connected to transferring the approaches to environmental screening.
Total Reflection X-ray Fluorescence (TXRF) is a small footprint, ressource efficient micro-analytical tool for trace elemental determination. However, depending on the matrix TXRF is also challenging in several ways: the preparation of a representative aliquot maybe difficult for slurries, shading effects and matrix effects may occur and the applicability of an IS maybe hampered by interferences (fitting may be impaired as well) or inhomogeneities. It is therefore crucial to understand and if applicable mitigate the influence of the before mentioned phenomena. We have used the small volume approach using pL droplets to study shading in TXRF previously.Using this approach thin specimens in a favorable geometry are prepared with a well defined morphology; this way minimizing matrix effects and shading. To be used as standard it is also necessary to determine the delivered elemental amounts. Here we will present on the performance of a commercial ink-jet printer cartridge to deliver defined volumes and elemental amounts. The microscopic specimens obtained have been successfully applied to determine relative sensitivities in TXRF and prepare references to study coded apertures in grazing incidence full field micro-XRF.The homogeneous lateral distribution of analyte and IS may be probed by micro-XRF, to obtain information on alikeness of analyte and IS. To study the alikeness of the in depth distribution (film-like or particle-like) angle scans can deliver valuable data. Here we present first results on angle scans using a prototype GIXRF set up and a commercial TXRF instrument.
The combination of different silanes as starting materials and as a product of hydrolysis by several alcohols or water creates a range of hundreds of technical products for a wide range of applications. In recent years, functional trialkoxysilanes have proven to be multi-purpose organosilanes. Applications range from weather protection of buildings to additives for glass fiber industry, sealants, adhesives, coatings and paints to the modification of polymers.
Commercial benchtop NMR spectrometers have the potential to be used in silane chemistry as an online method for reaction monitoring and quality control. NMR nuclei of interest for silane products are 1H and 29Si. In a joint research cooperation between EVONIK and BAM, the applicability of low-field NMR spectroscopy for the chemical analysis of silanes was evaluated. It was shown how it can extend the application range where existing technologies like NIR, Raman, UV/VIS, etc. cannot be used quantitatively due to a lack of reference data.
In a first case study the process of hydrolysis and condensation was observed using online NMR analysis. For this purpose, the substituents of a trialkoxysilane are first hydrolyzed by adding water and corresponding silanols are formed, which can then bind to materials via SiOH functions and crosslink to form siloxane units. Another case study was dealing with the kinetics of the cleavage of a cyclic silane compound. Online NMR analysis was used both in the laboratory and in the manufacturing plant. For this purpose, a fully automated containment system was used, which enables the use of a commercial NMR spectrometer in ATEX-environments. In the third case study presented, quantitative 1H-NMR spectra were acquired on product mixtures of a trialkoxysilane and other components such as organic stabilizers, organotin compounds, an aromatic amine and organic peroxides. An automatic evaluation method based on Indirect Hard Modeling (IHM) was developed.
Trialkoxysilane haben sich in den vergangenen Jahren als vielseitig einsetzbare Organosilane erwiesen. Die Einsatzgebiete erstrecken sich vom Witterungsschutz von Bauwerken über haftvermittelnde Eigenschaften in der Glasfaserindustrie, bei Dicht- und Klebstoffen, in Farben und Lacken bis hin zur Modifizierung von polymeren Werkstoffen.
Kommerzielle Benchtop-NMR-Spektrometer haben das Potential auch im Bereich der Silanchemie als Online-Methode zur Reaktionsüberwachung und für die Qualitätskontrolle eingesetzt zu werden. Interessante NMR-Kerne für die oben genanntem Produkte sind 1H und 29Si. In einer gemeinsamen Forschungskooperation zwischen EVONIK und BAM wurde anhand verschiedener Fallstudien die Anwendbarkeit der Niederfeld-NMR-Spektroskopie zur chemischen Analyse von Silanen evaluiert. Im Zuge der Fallstudien wurde gezeigt, wie Niederfeld-NMR-Spektroskopie die Möglichkeiten der Konzentrationsmessung auf neue Anwendungsgebiete erweitert, in denen bestehende Technologien wie z. B. NIR, Raman, UV/VIS, etc. mangels Referenzdaten nicht quantitativ eingesetzt werden können.
Fallstudie 1: Oligomerisierung
Eine Fallstudie setzte dazu an, den Hydrolyse- und Kondensationsverlauf mit einer geeigneten Online-NMR-Analytik zu beobachten, den Reaktionsfortschritt der Hydrolyse und Kondensation auf dieser Basis besser zu verstehen und zu optimieren. Zu diesem Zweck werden durch Zugabe von Wasser zunächst die Alkoxysubstituenten eines Trialkoxysilans hydrolysiert und entsprechende Silanole gebildet. Diese können dann über eine SiOH-Funktion an den zu modifizierenden Werkstoff anbinden und über weitere Silanolgruppen unter Ausbildung von Siloxaneinheiten vernetzen.
Fallstudie 2: Spaltung von cyclischen Silanverbindungen
In einer weiteren Fallstudie wurde die Kinetik der Aufspaltungen einer cyclischen Silanverbindung untersucht. Die Online-NMR-Analytik kam hierbei sowohl im Labor als auch in der industriellen Produktionsanlage zum Einsatz. Hierfür wurde eine vollständig automatisierte Einhausung verwendet, welche den Einsatz eines kommerziellen NMR-Spektrometers in explosionsgeschützten Bereichen ermöglicht.
Fallstudie 3: Qualitätskontrolle für Produktmischungen von Trialkoxysilanen
Für Produktmischungen eines Trialkoxysilans und weiteren Bestandteilen wie u. a. org. Stabilisatoren, Organozinnverbindungen, eines aromatischen Amins und org. Peroxide wurden quantitative 1H-Spektren akquiriert und eine automatische Auswertungsmethode basierend auf Indirect Hard Modeling (IHM) entwickelt. Für die Nebenkomponenten, deren Stoffmengenanteile bis zu 3 Mol-% betragen, wurden durch die zugrunde gelegte Methode typischerweise korrekte experimentelle Stoffmengenanteile gefunden, die weniger als 0,2 Mol-% vom Referenzwert abweichen.
Industrielle Anwendungen der Niederfeld-NMR-Spektroskopie für die Qualitätskontrolle von Silanen
(2021)
Aus der Kombination verschiedener Silane als Ausgangsstoffe und als Produkt der Hydrolyse durch eine Reihe von Alkoholen oder Wasser ergibt sich eine Palette von hunderten technischen Produkten für verschiedenste Anwendungen. Funktionelle Trialkoxysilane haben sich in den vergangenen Jahren als vielseitig einsetzbare Organosilane erwiesen. Die Einsatzgebiete erstrecken sich vom Witterungsschutz von Bauwerken über haftvermittelnde Eigenschaften in der Glasfaserindustrie, bei Dicht- und Klebstoffen, in Farben und Lacken bis hin zur Modifizierung von polymeren Werkstoffen.
Kommerzielle Benchtop-NMR-Spektrometer haben das Potential auch im Bereich der Silanchemie als Online-Methode zur Reaktionsüberwachung und für die Qualitätskontrolle eingesetzt zu werden. Interessante NMR-Kerne für die oben genanntem Produkte sind 1H und 29Si. In einer gemeinsamen Forschungskooperation zwischen EVONIK und BAM wurde anhand verschiedener Fallstudien die Anwendbarkeit der Niederfeld-NMR-Spektroskopie zur chemischen Analyse von Silanen evaluiert. Die Möglichkeiten der Konzentrationsbestimmung erweitern die Anwendungsgebiete, in denen bestehende Technologien wie z. B. NIR, Raman, UV/VIS, etc. mangels Referenzdaten nicht quantitativ eingesetzt werden können.
Eine Fallstudie setzte dazu an, den Hydrolyse- und Kondensationsverlauf mit geeigneter Online-NMR-Analytik zu beobachten, den Reaktionsfortschritt der Hydrolyse und Kondensation auf dieser Basis besser zu verstehen und zu optimieren. Zu diesem Zweck werden durch Zugabe von Wasser zunächst die Alkoxysubstituenten eines Trialkoxysilans hydrolysiert und entsprechende Silanole gebildet. Diese können dann über eine SiOH-Funktion an den zu modifizierenden Werkstoff anbinden und über weitere Silanolgruppen unter Ausbildung von Siloxaneinheiten vernetzen. In einer weiteren Fallstudie wurde die Kinetik der Aufspaltungen einer cyclischen Silanverbindung untersucht. Die Online-NMR-Analytik kam hierbei sowohl im Labor als auch in der industriellen Produktionsanlage zum Einsatz. Hierfür wurde eine automatisierte Einhausung verwendet, welche den Einsatz eines kommerziellen NMR-Spektrometers in explosionsgeschützten Bereichen ermöglicht.
Die Wettbewerbsfähigkeit der Prozessindustrie basiert auf der Sicherung der geforderten Produktqualität bei einer optimalen Nutzung von Anlagen, Rohstoffen und Energie. Ein Weg zur wissensbasierten Produktion führt über die Betrachtung der wesentlichen Apparate-, Prozess- und Freigabedaten aus Betrieben und Labors. Das Potenzial dieser Daten wird heute vielfach noch nicht konsequent für ein umfassendes Verständnis der Produktion genutzt.
Neben Fragen zur Datenerfassung, Datenkonnektivität und Datenintegrität müssen solche Daten für eine ganzheitliche Prozessanalyse zunächst mit Kontextinformationen zusammengebracht werden. Datenquellen enthalten Zeitwertpaare, aber auch diskrete Daten aus LIMS (Laboratory Information Management Systems) oder ELN (Electronic Laboratory Notebooks) und werden zunehmend durch 2D- und 3D-Daten aus der Chromatographie-Massenspektrometrie oder bildbasierter Analytik ergänzt.
Für die automatisierte Merkmalsextraktion, etwa zur Extraktion chemischer Informationen aus den oben genannten Datenquellen werden multivariate Werkzeuge und Algorithmen genutzt. Multivariate Statistiken wie PCA (Principle Component Analysis), PLS (Partial Least Squares) und LDA (Latent Discriminant Analysis) bilden die erste Grundlage für die Datenanalyse. Für diese Verfahren sind heute Datenvorbehandlungsschritte nötig. Die Modellbildung geschieht manuell und ist sehr aufwendig.
Können diese Daten im Zeitalter von ML (Machine Learning) und KI (Artificial Intelligence) anderweitig sinnvoll genutzt werden und ohne klassische Modellbildung? Die Bezeichnung „Big Data“ als Voraussetzung für datengetriebene Auswerteverfahren ist für die Prozessindustrie allerdings unpassend, denn auch bei mengenmäßig großen Datensätzen liegen für Kampagnen typischerweise nur Informationen über einige Batches mit einer Serie von Messdaten vor, die genügend Varianz für eine datengetriebene Auswertung aufweisen – nicht vergleichbar mit den Datenmengen im WWW oder von großen Internet-Konzernen.
Ein Weg zur wissensbasierten Produktion führt über die Betrachtung der wesentlichen Apparate-, Prozess- und Freigabedaten aus Betrieben und Labors. Das Potenzial dieser Daten wird heute vielfach noch nicht konsequent für ein umfassendes Verständnis der Produktion genutzt.
Neben Fragen zur Datenerfassung, Datenkonnektivität und Datenintegrität müssen solche Daten für eine ganzheitliche Prozessanalyse zunächst mit Kontextinformationen zusammengebracht werden. Datenquellen enthalten vor allem Zeitwertpaare, die numerisch vorbehandelt und möglichst vollautomatisch ausgewertet werden müssen. Am Beispiel NMR-spektroskopischer Daten wird der Stand der Auswertung mit physikalisch motivierten Modellen, wie z. B. dem IHM erläutert.
This contribution provides an overview of the BAMline synchrotron radiation beamline, which specializes in hard X-ray spectroscopy techniques for materials research. The BAMline offers X-ray absorption spectroscopy (XAS), x-ray fluorescence spectroscopy (XRF), and tomography to study materials' electronic structure, chemical composition, and structure. Key capabilities include standard and dispersive XAS for electronic structure, micro-XRF for elemental mapping, coded aperture imaging, and depth-resolved grazing exit XAS. The BAMline enables in situ characterization during materials synthesis and functions for energy, catalysis, corrosion, biology, and cultural heritage applications.
Ongoing developments like the implementation of machine learning techniques for experiment optimization and data analysis will be discussed. For instance, Bayesian optimization is being used to improve beamline alignment and scanning. An outlook to the future, where the BAMline will continue pioneering dynamic and multi-scale characterization, aided by advanced data science methods, to provide unique insights into materials research, will be given.
Chemical and pharmaceutical companies need to find new ways to survive successfully in a changing environment, while finding more flexible ways of product and process development to bring their products to market faster - especially high-value, high-end products such as fine chemicals or pharmaceuticals. This is complicated by changes in value chains along a potential circular economy.
One current approach is flexible and modular chemical production units that use multi-purpose equipment to produce various high-value products with short downtimes between campaigns and can shorten time-to-market for new products. Online NMR spectroscopy will play an important role for plant automation and quality control, as the method brings very high linearity, matrix independence and thus works almost calibration-free. Moreover, these properties ideally enable automated and machine-aided data analysis for the above-mentioned applications.
Using examples, this presentation will outline a possible more holistic approach to digitalization and the use of machine-based processes in the production of specialty chemicals and pharmaceuticals through the introduction of integrated and networked systems and processes.
The competitiveness of the process industry is based on ensuring the required product quality while making optimum use of equipment, raw materials and energy. Chemical companies have to find new paths to survive successfully in a changing environment, while also finding more flexible ways of product and process development to bring their products to market more quickly – especially high-quality high-end products like fine chemicals or pharmaceuticals. The potential of digital technologies belongs to these.
One way is knowledge-based production, taking into account all essential equipment, process and regulatory data of plants and laboratories. Today, the potential of this data is often not yet consistently used for a comprehensive understanding of production. Another approach uses flexible and modular chemical plants, which can produce different high-quality products using multi-purpose equipment with short downtimes between campaigns and reduce the time to market of new products. Digital transformation is enabling completely new production concepts that are being used increasingly. Intensified continuous production plants also allow for difficult to produce compounds.
This contribution aims to encourage a more holistic approach to the digitalization and use of machine-assisted methods in (bio) process engineering by introduction of integrated and networked systems and processes, which have the potential to speed up the high-quality production of specialty chemicals and pharmaceuticals.
Chemical and pharmaceutical companies have to find new paths to survive successfully in a changing environment, while also finding more flexible ways of product and process development to bring their products to market more quickly – especially high-quality high-end products like fine chemicals or pharmaceuticals. The potential of digital technologies belongs to these.
A current approach uses flexible and modular chemical production units, which can produce different high-quality products using multi-purpose equipment with short downtimes between campaigns and reduce the time to market of new products. At the same time, we need to move towards knowledge-based production that takes into account all essential equipment, process and control data from plants and laboratories and makes valuable expertise available and transferable. The potential of data from production together with its contextual information is often not yet consistently used today for a comprehensive understanding of production.
By giving examples this paper outlines a possible more holistic approach to digitalisation and the use of machine-based methods in the production of specialty chemicals and pharmaceuticals through the introduction of integrated and networked systems and processes.
Unternehmen der Prozessindustrie müssen neue Wege finden, um in einem sich wandelnden Umfeld erfolgreich zu überleben, und gleichzeitig flexiblere Wege der Produkt- und Prozessentwicklung finden, um ihre Produkte schneller auf den Markt zu bringen – insbesondere hochwertige, hochwertige Produkte wie Feinchemikalien oder Arzneimittel. Dies wird zukünftig durch Veränderungen in den Wertschöpfungsketten entlang einer potenziellen Kreislaufwirtschaft erschwert.
Anhand von Beispielen wird in diesem Vortrag ein möglicher ganzheitlicher Ansatz zur Digitalisierung und zum Einsatz maschineller Verfahren in der Produktion von Spezialchemikalien durch die Einführung integrierter und vernetzter Systeme und Prozesse skizziert.
Es wird auch auf die aktuelle Technologie-Roadmap „Prozess-Sensoren 2027+“ eingegangen, die Ende 2021 erschienen ist. Im Zentrum dieser Roadmaps stehen Sensoren zur Erfassung von physikalischen und chemischen Messgrößen mittels spezifischer und unspezifischer Messverfahren, die zur Steuerung und dem besseren Verständnis von Prozessen dienen. Die Roadmap fasst die gemeinsame Technologie- und Marktsicht von Anwendern, Herstellern und Forschungs¬einrichtungen im Bereich Prozess-Sensorik in der verfahrenstechnischen Industrie zusammen. Digitalisierung und Nachhaltigkeit sind übergreifende Kernthemen der künftigen Entwicklung.
Anhand von Beispielen wird in diesem Vortrag ein möglicher ganzheitlicherer Ansatz für die Digitalisierung und den Einsatz maschinengestützter Prozesse bei der Herstellung von Spezialchemikalien und Arzneimitteln durch die Einführung integrierter und vernetzter Systeme und Prozesse skizziert. Ein aktueller Ansatz und ein Beispiel in diesem Vortrag sind flexible und modulare chemische Produktionseinheiten, die Mehrzweckanlagen nutzen, um verschiedene hochwertige Produkte mit kurzen Stillstandszeiten zwischen den Kampagnen herzustellen und die Markteinführungszeit für neue Produkte zu verkürzen.
Als zweites Beispiel wird kurz die Testplattform Wasserstofftankstelle vorgestellt, die als moderne Anlage der Prozessindustrie betrachtet werden kann, vergleichbar mit einer Anlage aus der chemischen oder pharmazeutischen Industrie. An ihr lassen sich alle derzeit entlang der Digitalen Transformation diskutierten Konzepte implementieren, um sie zu standardisieren und zu validieren. Dazu gehören Konzepte zur Konnektivität von Sensoren und Aktoren aus der Feldebene in höhere Ebenen der Automatisierung oder zur Einbringung zusätzlicher Sensoren oder Sensornetzwerke, die zunehmend flexibler gestaltet werden soll, die sichere und nachvollziehbare Parametrierung von Automatisierungskomponenten – vielleicht aus einem digitalen Abbild (Verwaltungsschale bzw. „Digitaler Zwilling“) heraus, Konzepte zur vorausschauenden Wartung („Predictive Maintenance“), Konzepte zu digitalen Entscheidungsprozessen, Zertifikaten und Signaturen oder der zunehmende Einsatz von komplexen Auswertungsalgorithmen und Applikationen in der Feldebene („Embedded Computing“) oder der „Kante“ zu Cloudbasierten Systemen der Informationstechnik („Edge-Computing“).
Die beiden Beispiele sollen aktuelle Entwicklungsachsen des industriellen Messwesens im Rahmen der industriellen Automation aufzeigen, in denen Messwerte, deren Messunsicherheiten und Kontextinformationen eine wichtige Rolle einnehmen.
Integrierte und vernetzte Systeme und Prozesse – Eine Perspektive für die smarte Laborinfrastruktur
(2022)
Chemie- und Pharmaunternehmen müssen neue Wege gehen, um in einem sich wandelnden Umfeld erfolgreich zu überleben, und gleichzeitig flexiblere Wege der Produkt- und Prozessentwicklung finden, um ihre Produkte schneller auf den Markt zu bringen - vor allem hochwertige High-End-Produkte wie Feinchemikalien oder Arzneimittel. Dazu gehört auch das Potenzial der digitalen Technologien, um ein umfassenderes Wissensmanagement zu ermöglichen.
Eine wichtige Wissensquelle sind analytische Labors, die Unternehmensweit aktiv sind – von F&E bis zur Produktion. Die ganzheitliche Einbindung von analytischen Labors und ein unternehmensweites Daten- und Wissensmanagement sind wichtige Bausteine zur Integration und Vernetzung aller Systeme und Prozesse. Das Potenzial von Daten aus der Produktion mit ihren Kontextinformationen wird heute oft noch nicht konsequent für ein umfassendes Verständnis der Produktion genutzt.
Dieser Beitrag skizziert anhand von Beispielen einen möglichen ganzheitlicheren Ansatz zur Digitalisierung und zum Einsatz maschineller Verfahren in der Produktion von Spezialchemikalien und Pharmazeutika durch die Einführung integrierter und vernetzter Systeme und Prozesse.
Due to its advantages of being a direct comparison method, quantitative NMR spectroscopy (qNMR) becomes more and more popular in industry. While conventional high-field NMR systems are often associated with high investment and operational costs, the upcoming market of permanent-magnet based benchtop NMR systems show a considerable option for a lot of applications. The mobility of these systems allows to bring them more closely to the real production environment, e.g. for at-line quality control.
In this work we present an interlaboratory comparison study investigating the qNMR performance of state-of-the-art benchtop NMR spectrometers. Therefore, BAM prepared two samples of a mixture of NMR reference standards tetramethylbenzene (TMB) and tetrachloronitrobenzene (TCNB) at concentration levels of 200 mM and 10 mM. These “ready-to-use” samples were sent to participant laboratories, which performed analysis on their benchtop NMR equipment of different vendors and fields from 43 to 80 MHz. Raw data was reported back and further investigated by using different data analysis methods at BAM.
After this very first qNMR comparison study of benchtop NMR spectrometers show promising results, following studies are planned to cover more parts of the qNMR process, e.g. sample preparation and weighing, but also data analysis, as commonly done in similar studies for high-field NMR spectroscopy in industry and metrology.
Investigation of degradation of the aluminum current collector in lithium-ion batteries by GD-OES
(2022)
Lithium-ion batteries (LIBs) are one technology to overcome the challenges of climate and energy crisis. They are widely used in electric vehicles, consumer electronics, or as storage for renewable energy sources. However, despite innovations in batteries' components like cathode and anode materials, separators, and electrolytes, the aging mechanism related to metallic aluminum current collector degradation causes a significant drop in their performance and prevents the durable use of LIBs. Glow-discharge optical emission spectroscopy (GD-OES) is a powerful method for depth-profiling of batteries' electrode materials. This work investigates aging-induced aluminum deposition on commercial lithium cobalt oxide (LCO) batteries' cathodes. The results illustrate the depth-resolved elemental distribution from the cathode surface to the current collector. An accumulation of aluminum is found on the cathode surface by GD-OES, consistent with results from energy-dispersive X-ray spectroscopy (EDX) combined with focused ion beam (FIB) cutting. In comparison to FIB-EDX, GD-OES allows a fast and manageable depth-profiling. Results from different positions on an aged cathode indicate an inhomogeneous aluminum film growth on the surface. The conclusions from these experiments can lead to a better understanding of the degradation of the aluminum current collector, thus leading to higher lifetimes of LIBs.
The knowledge of transformation pathways and identification of transformation products (TPs) of veterinary drugs is important for health, food and environmental matters. Monensin (MON) is an ionophore antibiotic widely used to cure and prevent coccidiosis by chicken especially in broiler farming. Residues are not only found in food products (chicken and eggs) but also in the environment (manure, soil or water). Several transformation processes can alter the parent compound MON, ranging from biotransformation in living organism to biotic/abiotic and microbial processes in environmental matters.
The main objective of this work was to investigate the potential of electrochemistry (EC) to simulate oxidative transformation processes and to predict TPs of MON. An electrochemical reactor was used consisting of a flow-through cell with a glassy carbon working electrode. Derived TPs were analyzed by online coupling of EC and high-resolution mass spectrometry (HRMS) and LC-HRMS offline measurements. Among the generated TPs already known as well as unknown TPs of MON could be found.
Additionally, MON was subjected also to other transformation methods such as Fenton reaction, photochemical and hydrolysis experiments as well as metabolism tests with microsomes. As a result, different targeted and suspected TPs could be identified by analysis with LC-HRMS.
An overview of detected/identified TPs from this study will be presented in comparison to literature known metabolites and TPs.
Vanadium redoxflow batteries (VRFB)are currently one of the most promising candidates for stationary energys torage.For large scale applications the ion conducting membranes currently in use need to be improved. Ideally,they need to become more cost efficient and selective regarding the vanadium crossover.For a better understanding of the vanadium crossover, the development of reliable analytical methods and procedures, that elucidate uptake and transport of vanadium ions in the membrane, is necessary. First, we present the uptake of V2+,V3+,VO2+, VO2+ and V2O33+ in Nafion™ and in a novel membrane based onpoly(1,1-difluoroethylene)(PVDF). In preliminary discharge/charge experiments the ETFE-based membrane, the precursor of PVDF-based membrane, performed comparable to Nafion™. The methods of choice for speciation are UV/Vis and X-ray absorption near edge structure spectroscopy (XANES). According to the results, V2O33+, formed from VO2+ and VO2+, diffuses also into the membrane. In present models, the diffusion of V2O33+ is neglected. In addition,we study whether reactions could take place inside the membranes’ nanoscopic water body using XANES. Exposing Nafion™ from one site with V3+a nd from the other site with VO2+ realized the experiment. The results verified that VO2+ was formed inside the membrane. However,in present models reactions inside the membrane are neglected, too.
IRWG strategy update
(2023)
Isotope analysis can be used to determine the age and provenance of geological samples. Modern techniques in optical spectrometry allow us a stand-off isotope analysis. This seminar will discuss how planetary science with the next Moon and Mars missions drive optical spectrometry into precise and accurate isotope analysis and how BAM will contribute.
Lithium (Li), Boron (B), Nitrogen (N), Magnesium (Mg), and Calcium (Ca) are pivotal elements across various spheres such as the hydrosphere, biosphere, and lithosphere, significantly impacting (bio-) geochemical and physiological processes. These elements exhibit stable isotopes with substantial roles in geological, environmental, and biological studies. The traditional method for measuring isotope amount ratios has been through mass spectrometry, which, despite its accuracy, comes with high operational costs, the need for skilled operators, and time-consuming sample preparation processes.
Combining optical spectroscopy with chemometrics introduces an innovative, cost-effective approach by the hand of high-resolution continuum source atomic and molecular absorption spectrometry (HR-CS-AAS and HR-CS-MAS) for the analysis of isotope ratios in Li, B, N, Mg, and Ca. By analyzing the atomic or molecular absorption spectrum of the in-situ generated cloud of atoms of diatomic molecules (e.g., Li, BH, NO, MgF, CaF) during the electronic transition from the fundamental state, this method allows for the rapid determination of isotope ratios directly from sample solutions without the need for complex sample preparation.
For each element, the respective atomic or molecule's absorption spectrum was deconvoluted into its isotopic components using partial least squares regression or machine learning algorithms. Robust calibration models were developed, calibrated with enriched isotope, and validated against certified reference materials. Spectral data underwent preprocessing to optimize the modeling to determine the optimal number of latent variables.
The findings showcase that this optical spectrometric method yields results that agree with those obtained via inductively coupled plasma mass spectrometry (ICP-MS), offering a promising, cost-effective, and rapid alternative for isotope analysis with precisions as low as ± 0.2‰. This approach is a significant advancement in analytical chemistry, providing a new way to study isotope variations in biological, environmental, and geological samples.
Isotope Ratio Analysis
(2023)
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.
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.
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.
Isotope analysis can be used to determine the age and provenance of geological samples or to study dynamic systems like Li-ion batteries. Modern techniques in optical spectrometry allow us a fast and slow-cost isotope analysis. These techniques include high-resolution continuum source molecular absorption spectrometry (HR-CS-MAS) and laser ablation molecular isotopic spectrometry. This seminar will discuss our recent work on precise and accurate isotope analysis of boron, magnesium, and lithium with geology, climate, and energy research applications.
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.
Monitoring programs should generate high-quality data on the concentrations of substances and other pollutants in the aquatic environment to enable reliable risk assessment. Furthermore, the need for comparability over space and time is critical for analysis of trends and evaluation of restoration of natural environment. Additionally, research work and exercises at the European level have highlighted that reliable measurements of estrogenic substances at the PNEC level are still challenging to achieve. The project EDC-WFD “Metrology for monitoring endocrine disrupting compounds under the EU Water Framework Directive” aims to develop traceable analytical methods for determining endocrine disrupting compounds and their effects, with a specific focus on three estrogens of the first watch list (17-beta-estradiol (17βE2), 17-alpha-ethinylestradiol (EE2), and estrone (E1)). Estrogens 17-alpha-estradiol (17aE2) and estriol (E3) will be included to demonstrate the reliability of the developed methods - Mass Spectrometry based method and effect-based methods (EBM) - and to support the requirements of Directive 2013/39/EC, Directive 2009/90/EC and Commission Implementation Decision (EU) 2018/840, hence improving the comparability and compatibility of measurement results within Europe. During the EDC-WFD project four EBM will be deeply investigated in order to improve their rationale use and their support in water quality assessment.
Die Identifizierung von Transformationsprodukten (TPs) von Tierarzneimittelwirkstoffen ist wichtig für Gesundheit, Lebensmittel und Umwelt. Monensin (MON) gehört zu den Ionophoren Antibiotika und wird genutzt zum Schutz und zur Behandlung von Kokzidiose bei Geflügel, vorwiegend prophylaktisch in der Geflügelmast. Rückstände können in tierischen Produkten (Geflügel und Eier) aber auch in der Umwelt (Tiermist, Gewässer, Böden) gefunden werden. Verschiedene Transformationsprozesse können auftreten, beginnend bei der Biotransformation in lebenden Organismen bis hin zu biotischen und abiotischen Prozessen in der Umwelt.
Die Kopplung von Elektrochemie und Massenspektrometrie, kurz EC/HRMS, als rein instrumenteller Ansatz zur Simulation von Transformationsprodukten ist seit vielen Jahren in der pharmazeutischen Forschung etabliert. Hierbei wird mithilfe einer elektrochemischen Durchflusszelle der oxidative Metabolismus einer Substanz simuliert und zugleich analysiert. Unter Verwendung von EC/HRMS und LC-HRMS wurde MON elektrochemisch bei Potentialen bis zu 2.5 V vs Pd/H2 oxidiert und die entstehenden TPs mit Metabolismustests mit Rattenlebermikrosomen verglichen. Als Ergebnis wurden verschiedene TPs von MON gefunden und Strukturvorschläge wurden erstellt. Ein Überblick über die detektierten und identifizierten TPs wird dargestellt.
Mykotoxine werden als sekundäre Metabolite von Schimmelpilzen gebildet und haben diverse schädliche Effekte auf Menschen, Tiere und Pflanzen. Laut FAO sind weltweit bis zu 25 % aller Lebens- und Futtermittel mit Mykotoxinen kontaminiert, wodurch jährlich immense ökonomische Verluste entstehen.
Neben den eigentlichen Mykotoxinen rücken zunehmend deren Transformationsprodukte (TPs) in den Fokus. Diese können als natürliche Stoffwechselprodukte toxischer sein als das eigentliche Mykotoxin und stellen eine potenzielle zusätzliche Gefahr für den Verbraucher dar. TPs werden überwiegend mit in vitro und in vivo Techniken untersucht, welche sowohl zeit- als auch kostenintensiv sind. Ziel war es nun, schnelle und zudem verlässliche Techniken zur Simulation von TPs diverser Mykotoxine zu testen. Die Kopplung von Elektrochemie und Massenspektrometrie, kurz EC/MS, als rein instrumenteller Ansatz ist seit vielen Jahren in der pharmazeutischen Forschung etabliert. Hierbei wird mithilfe einer elektrochemischen Durchflusszelle der oxidative Metabolismus einer Substanz simuliert und zugleich analysiert.
Unter Verwendung von EC/MS, EC/LC/MS und HPLC-MS Techniken (MS/MS und FT-ICR) wurden nun die Mykotoxine Zearalenon, Citrinin und Dihydroergocristin (als Modellsubstanz für die Ergotalkaloide) elektrochemisch bei Potentialen bis zu 2500 mV vs. Pd/H2 oxidiert und deren TPs mit mikrosomalen in vitro Ansätzen verglichen. Hierbei konnten mehrere Übereinstimmungen hydroxylierter Spezies, sowohl elektrochemisch als auch biochemisch generiert, festgestellt werden. Die EC/MS ist somit auch in der Lebensmittelanalytik als nützliches und vielseitiges Werkzeug verwendbar.
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.
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.
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.
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.
ISO/IEC 17025 is the worldwide quality standard for testing and calibration laboratories. It is the basis for accreditation by an accreditation body. The current version was published in 2018.
Implementing ISO/IEC 17025 as part of laboratory quality initiatives offers both laboratory and business benefits, such as expanding the potential customer base for testing and/or calibration, increasing the reputation and image of the laboratory at national and international level, continuous improvement of the data quality and the effectiveness of the laboratory or creation of a good basis for most other quality systems in the laboratory sector, such as GxP. The main difference between a proper approach to analysis and a formal accreditation is shown in a targeted documentation, especially on the qualification of the personnel, the test equipment and the validation of the analytical methods.
Using quantitative NMR spectroscopy as an example, it is shown how accreditation can be carried out and what documentation is required. In our case, we have described the procedure in an SOP ("Determination of the quantitative composition of simple mixtures of structurally known compounds with 1H-NMR spectroscopy") and supported it with a modular system of organizational and equipment SOPs. The special feature is that the accredited method is independent for the choice of the analyte and the matrix and therefore it is possible to operate with a single validated method. In our case, we have proposed three quality levels ("leagues") with different levels of analytical effort, which differ in their measurement uncertainty, in order to simplify the workflow and analysis design.
Laser-induced plasmas are widely used in many areas of science and technology; examples include spectrochemical analysis, thin film deposition, material processing, and even jet propulsion. Several topics will be addressed. First, general phenomenology of laser-induced plasmas will be discussed. Then, a chemical model will be presented based on a coupled solution of Navier-Stokes, state, radiative transfer, material transport, and chemical (Guldberg-Waage) equations. Results of computer simulations for several chemical systems will be shown and compared to experimental observations obtained by optical imaging, spectroscopy, and tomography. The latter diagnostic tools will also be briefly discussed.
Calcium isotope analysis can be an important tool for paleoclimate studies of the carbon cycle, as well in carbon capture technology, but its utility is limited by challenges using conventional mass spectrometry. We propose a new fast, precise, and high-throughput technology based on multiple complementary high-resolution spectroscopies analyzed by machine-learning.
An overview of personal experience with laser-induced plasma (LIP) will be given. The combination of LIP with laser-induced fluorescence, atomic absorption, Raman spectroscopy and spatial heterodyne spectroscopy for elemental and isotopic analysis will be discussed. Unusual applications of LIP will be covered, such as LIP-based lasers and LIP-based chemical reactors.
Flexible and modular chemical plants can produce various high-quality products using multi-purpose equipment with short down-times between campaigns and reduce time to market for new products. Intensified continuous production plants allow for difficult to produce compounds.
Therefore, fully automated “chemical” process control along with real-time quality control are prerequisites to such concepts and thus should be based on “chemical” information. The advances of a fully automated NMR sensor were exploited, using a given pharmaceutical lithiation reaction as an example process within a modular pilot plant. A commercially available benchtop NMR spectrometer was integrated to the full requirements of an automated chemical production environment such as , e.g., explosion safety, field communication, and robust evaluation of sensor data. It was thereof used for direct loop advanced process control and real-time optimization of the process. NMR appeared as preeminent online analytical tool and allowed using a modular data analysis tool, which even served as reliable reference method for further PAT applications.
The talk also generally covers current aspects of high-field and low-field online NMR spectroscopy for reaction monitoring and process control and gives also an overview on direct dissolution studies of API cocrystals.
Die Probenpräparation ist ein wichtiger Schritt für die Qualität der Massenspektren in MALDI-TOF MS. Es werden Polymerproben, die lösungsmittelbasiert und lösungsmittelfrei präpariert worden sind, verglichen. Dabei werden die Intensitätsverhältnisse von ternären Mischungen von PEG-, PS- und PMMA-Polymeren beachtet.
In this talk I’ll describe the use of artificial neural networks (ANN) for quantifying X-ray fluorescence (XRF) measurements. The main idea of this talk is to give an overview of the process needed to generate a model that can then be applied to a specific problem.
In XRF, a sample is excited with X-rays and the resulting characteristic radiation is detected to determine elements quantitatively and qualitatively. This is traditionally done in several time-consuming steps. I’ll show the possibilities and problems of using a neural network to realise a "one-click" quantification. This includes generating training data using Monte Carlo simulation and augmenting the existing data set with an ANN to generate more data. The search for the optimal hyperparameters, manually and automatically, is also described. For the case presented, we were able to train a network with a mean absolute error of 0.1% by weight for the synthetic data and 0.7% by weight for a set of experimental data obtained with certified reference materials.
In X-ray fluorescence (XRF), a sample is excited with X-rays, and the resulting characteristic radiation is detected to detect elements quantitatively and qualitatively. Quantification is traditionally done in several steps:
1. Normalization of the data
2. Determination of the existing elements
3. Fit of the measured spectrum
4. Calculation of concentrations with fundamental parameters / MC simulations / standard based
The problem with standard based procedures is the availability of corresponding standards. The problem with the calculations is that the measured intensities for XRF measurements are matrix-dependent. Calculations must, therefore, be performed iteratively (= time consuming) in order to determine the chemical composition.
First experiments with gold samples have shown the feasibility of machine learning based quantification in principle. A large number of compositions were simulated (> 10000) and analyzed with a deep learning network. For first experiments, an ANN (Artificial Neural Network) with 3 hidden layers and 33x33x33 neurons was used. This network learned the mapping of spectra to concentrations using supervised learning by multidimensional regression. The input layer was formed by the normalized spectrum, and the output layer directly yielded the searched values. The applicability for real samples was shown by measurements on certified reference materials.
Various applications for artificial intelligence in the context of spectroscopy will be presented. in particular, examples from BAMline will be presented. After a short introduction to synchrotron radiation, artificial intelligence algorithms for the quantification of X-ray fluorescence measurement are discussed. In the second example, information retrieval by natural language processing is discussed.
Natural sciences play auxiliary role in the studies of manuscripts. The success of their contribution depends strongly on the formulation of the question and the choice of the methods to obtain the requested answer. Therefore, one should try to go beyond the understanding of the basic principles of the scientific analysis.
We will start with a glance at the basic principles of the techniques used in the material science for determination of the elemental composition (X-ray emission) and molecular composition (FTIR & Raman). We will move then to the bench and mobile equipment commonly used in the field of cultural heritage. At the end we will choose a question to be answered and design an ideal experiment that will be modified according to the limitations dictated by on-site conditions.
In the ateliers in the afternoon we will
a) compare two XRF devices that differ in their spatial resolution;
b) use a high resolution microscope (Keyence) to obtain a close look at writing surfaces and materials;
c) we will learn to determine the type of the inks with the help of another microscope (DinoLite AD413T-12V), a usb microscope with visible, UV and NIR illumination;
d) we will learn to use FTIR-ATR device for determination of the type of the writing surface;
e) We will use mobile Raman device for identification of pigments.
Our study is dedicated to non-destructive characterization of the support and the inks of the DSS.
To that aim we use micro-XRF, 3D- SY-XRF, different IR methods including synchrotron radiation based reflectance spectroscopy, optical and electron microscopy.
The lecture discusses advantages and the shortcomings of the non-destructive testing approach.
Synchrotron radiation sources with their unique properties in terms of intensity, polarization and adjustability offer a wide range of possibilities in materials research. A basic introduction about the creation and special properties of synchrotron radiation will be given. Examples of current work at BAMline, the high-energy measuring facility of the Federal Institute for Materials Research and Testing at the synchrotron BESSY, are used to illustrate the possibilities and limitations of existing measuring methods. It will be shown how the formation of corrosion layers can be tracked, how the abrasion of implants leads to the introduction of heavy metals into the surrounding bone matrix and how the detection of smallest impurities in gold is possible by optimizing the measuring conditions. Finally, an outlook at the hardware and software developments to be expected in the coming years is given.
Ein Durchlaufkühler ist im Betrieb explodiert. Die zerborstenen Gehäuseteile aus Kunststoff führten zu einem Austreten der Kühlflüssigkeit am Betriebsort sowie zu einem Personenschaden mit Knalltrauma. Bei Funktionsprüfungen am beschädigten Gerät traten unerwartet, aber reproduzierbar Knalleffekte auf der Kupfer-Kühlschlange auf. Ein möglicher Mechanismus konnte im Labor durch Synthese von Kupferazid auf Kupferproben und Auslösung vergleichbarer Knalleffekte nachgestellt werden. Damit ist die Plausibilität des beschriebenen Schadensereignisses mit diesem oder einem ähnlich reagierenden Stoff belegt. Ein eindeutiger Nachweis darüber, dass beim aufgetretenen Schadensfall dieselbe chemische Reaktion stattgefunden hat ist nicht möglich, da die Belag-Überreste aus dem explodierten Kühlgerät für eine Analyse nicht mehr in ausreichender Menge verfügbar waren.