Chemie und Prozesstechnik
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- 2019 (19) (entfernen)
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- ICP-MS (7)
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- Isotopic fractionation (1)
- LA-ICP-MS (1)
- Labeling (1)
- Laser ablation inductively coupled plasma–mass spectrometry imaging (LA-ICP-MSI) (1)
- Lead isotope composition (1)
- Lead isotope variations (1)
- MC-ICP-MS (1)
- Magnesium (1)
- Magnesium isotope ratios (1)
- Mass cytometry (1)
- Matrix-assisted laser desorption ionization–mass spectrometry imaging (MALDI-MSI) (1)
- Metrology (1)
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- Micro-sublimation (1)
- Ore provenance (1)
- Peptide library (1)
- Plant tissue (1)
- Pore fluids (1)
- Priam's treasure (1)
- Radiogenic isotopes (1)
- SC-ICP-MS (1)
- SI traceability (1)
- Sample-sample bracketing (1)
- Single cell-ICP-MS (1)
- Speroid (1)
- Spheroid (1)
- Trojan silver artefacts (1)
- bell pepper (1)
- boron (1)
- delta value (1)
- isotope fractionation (1)
- measurement uncertainty (1)
- metabolism (1)
Organisationseinheit der BAM
- 1.1 Anorganische Spurenanalytik (19) (entfernen)
During R/V Meteor cruise 141/1, pore fluids of near surface sediments were investigated to find indications for hydrothermal activity in the Terceira Rift (TR), a hyperslow spreading center in the Central North Atlantic Ocean. To date, submarine hydrothermal fluid venting in the TR has only been reported for the D. João de Castro seamount, which presently seems to be inactive. Pore fluids sampled close to a volcanic cone at 2,800‐m water depth show an anomalous composition with Mg, SO4, and total alkalinity concentrations significantly higher than seawater and a nearby reference core. The most straightforward way of interpreting these deviations is the dissolution of the hydrothermally formed mineral caminite (MgSO4 0.25 Mg (OH)2 0.2H2O). This interpretation is corroborated by a thorough investigation of fluid isotope systems (δ26Mg, δ30Si, δ34S, δ44/42Ca, and 87Sr/86Sr). Caminite is known from mineral assemblages with anhydrite and forms in hydrothermal recharge zones only under specific conditions such as high fluid temperatures and in altered oceanic crust, which are conditions generally met at the TR. We hypothesize that caminite was formed during hydrothermal activity and is now dissolving during the waning state of the hydrothermal system, so that caminite mineralization is shifted out of its stability zone. Ongoing fluid circulation through the basement is transporting the geochemical signal via slow advection toward the seafloor.
In most chemical reactions, stable isotopes are fractionated in a mass-dependent manner, yielding correlated isotope ratios in elements with three or more stable isotopes. The proportionality between isotope ratios is set by the triple isotope fractionation exponent θ that can be determined precisely for, e.g., sulfur and oxygen by IRMS, but not for metal(loid) elements due to the lower precision of MC-ICP-MS analysis and smaller isotopic variations. Here, using Mg as a test case, we compute a complete metrologically robust uncertainty budget for apparent θ values and, with reference to this, present a new measurement Approach that reduces uncertainty on θ values by 30%. This approach, namely, direct educt-product bracketing (sample−sample bracketing), allows apparent θ values of metal(loid) isotopes to be determined precisely enough to distinguish slopes in three-isotope space. For the example of Mg, we assess appropriate quality Control standards for interference-to-signal ratios and Report apparent θ values of carbonate−seawater pairs. We determined apparent θ values for marine biogenic carbonates, where the foraminifera Globorotalia menardii yields 0.514 ± 0.005 (2 SD), the coral Porites, 0.515 ± 0.006 (2 SD), and two specimens of the giant clam Tridacna gigas, 0.508 ± 0.007 (2 SD) and 0.509 ± 0.006 (2 SD), documenting differences in the uptake pathway of Mg among marine calcifiers. The capability to measure apparent θ values more precisely adds a new dimension to metal(loid) δ values, with the potential to allow us to resolve different modes of fractionation in industrial and natural processes.
Arraying of single cells for mass spectrometric analysis is a considerable bioanalytical challenge. In this study, we employ a novel single cell arraying technology for quantitative analysis and isotopic fingerprinting by laser ablation inductively coupled plasma time-of-flight mass spectrometry (LA-ICP-TOF-MS). The single cell arraying approach is based on a piezo-acoustic microarrayer with software for automated optical detection of cells within the piezo dispense capillary (PDC) prior to arraying. Using optimized parameters, single cell occupancy of >99%, high throughput (up to 550 cells per hour), and a high cell recovery of >66% is achieved. LA-ICP-TOF-MS is employed to detect naturally occurring isotopes in the whole mass range as fingerprints of individual cells. Moreover, precise quantitative determination of metal-containing cell dyes is possible down to contents of ∼100 ag using calibration standards which were produced using the same arrayer.
In the last decades, significant efforts have been made to investigate possible cytotoxic effects of metallic nanoparticles (NPs). Methodologies enabling precise information regarding uptake and intracellular distribution of NPs at the single cell level remain to be established. Mass cytometry (MC) has been developed for high-dimensional single cell analyses and is a promising tool to quantify NP−cell interactions. Here, we aim to establish a new MC-based quantification procedure to receive absolute numbers of NPs per single cell by using a calibration that considers the specific transmission efficiency (TE) of suspended NPs. The current MC-quantification strategy accept TE values of complementary metal solutions. In this study, we demonstrate the different transmission behavior of 50 nm silver NPs (AgNP) and silver nitrate solution. We have used identical AgNPs for calibration as for in vitro-differentiated macrophages (THP-1 cell line) in a time- and dose-dependent manner. Our quantification relies on silver intensities measuring AgNPs in the same detection mode as the cells. Results were comparable with the TE quantification strategy using AgNPs but differed when using ionic silver. Furthermore, intact and digested cell aliquots were measured to investigate the impact of MC sample processing on the amount of AgNPs/cell. Taken together, we have provided a MC-specific calibration procedure to precisely calculate absolute numbers of NPs per single cell. Combined with its unique feature of multiplexing up to 50 parameters, MC provides much more information on the single cell level than single cell-inductively coupled plasma mass spectrometry (SC-ICP-MS) and, therefore, offers new opportunities in nanotoxicology.
In the recent decade, metal pyrithione complexes have become important biocides for antifouling purposes in shipping. The analysis of metal pyrithione complexes and their degradation products/species in environmental samples is challenging because they exhibit fast UV degradation, transmetalation, and ligand substitution and are known to be prone to spontaneous species transformation within a chromatographic system. The environmental properties of the pyrithione species, e.g., toxicity to target and non-target organisms, are differing strongly, and it is therefore inevitable to identify as well as quantify all species separately. To cope with the separation of metal pyrithione species with minimum species transformation during analysis, a capillary electrophoresis (CE)–based method was developed. The hyphenation of CE with selective electrospray ionization- and inductively coupled plasma–mass spectrometry (ESI-, ICP-MS) provided complementary molecular and elemental information for the identification and quantification of pyrithione species. To study speciation of pyrithiones, a leaching experiment of several commercial antifouling paints containing zinc pyrithione in ultrapure and river water was conducted. Only the two species pyrithione (HPT) and dipyrithione ((PT)2) were found in the leaching media, in concentrations between 0.086 and 2.4 μM (HPT) and between 0.062 and 0.59 μM ((PT)2), depending on the paint and leaching medium. The limits of detection were 20 nM (HPT) and 10 nM ((PT)2). The results show that complementary CE-MS is a suitable tool for mechanistical studies concerning species transformation (e.g., degradation) and the identification of target species of metal pyrithione complexes in real surface water matrices, laying the ground for future environmental studies.
We applied high resolution laser ablation inductively coupled plasma time-of-flight mass spectrometry (LA-ICP-TOF-MS) with cellular spatial resolution for bioimaging of nanoparticles uptaken by fibroblast multicellular spheroids (MCS). This was used to quantitatively investigate interactions of silver nanoparticles (Ag NPs) and the distributions of intrinsic minerals and biologically relevant elements within thin sections of a fibroblast MCS as a three-dimensional in vitro tissue model. We designed matrix-matched calibration standards for this purpose and printed them using a noncontact piezo-driven array spotter with a Ag NP suspension and multielement standards. The limits of detection for Ag, Mg, P, K, Mn, Fe, Co, Cu, and Zn were at the femtogram (fg) level, which is sufficient to investigate intrinsic minerals in thin MCS sections (20 μm thick). After incubation for 48 h, Ag NPs were enriched in the outer rim of the MCS but not detected in the core. The localization of Ag NPs was inhomogeneous in the outer rim, and they were colocalized with a single-cell-like structure visualized by Fe distribution (pixel size of elemental images: 5 × 0.5 μm). The quantitative value for the total mass of Ag NPs in a thin section by the present method agreed with that obtained by ICP-sector field (SF)-MS with a liquid mode after acid digestion.
The most challenging part in performing a single cell ICP-MS (sc-ICP-MS) approach is the sample preparation, in particular the reduction of the ionic background. This step is, in many cases, time-consuming and required for each sample separately. Furthermore, sc-ICP-MS measurements are mostly carried out "manually", given the fact that present systems are not allowing for an automated change of samples. Thus, within this work, we developed an approach based on a HPLC system coupled on-line with sc-ICP-MS via a set of switching valves as well as an in-line filter for automated cell washing. This set-up enables the ionic background removal as well as analysis of single cells completely automated without any manual sample pretreatment. Our approach was applied for the analysis of the single celled diatom species Cyclotella meneghiniana, a marine diatom species, on the basis of Mg24 and facilitates testing in 11 min per sample, requiring only around 10,000 cells in a volume of 10 µL and approx. 10 mL of a 5% MeOH/95% deionized water (v/v) mixture. Even at extremely saline culturing media concentrations (up to 1000 mg L-1 magnesium) our on-line approach worked sufficiently allowing for distinction of ionic and particulate fractions. Furthermore, a set of diatom samples was analyzed completely automated without the need for changing samples manually. So, utilizing this approach enables analyzing a high quantity of samples in a short time and therefore in future the investigation of ecotoxicological effects is simplified for example in terms of metal accumulation by taking biovariability into account.
We investigated the penetration of silver nanoparticles (Ag NPs) into a three-dimensional in vitro tissue analog using NPs with various sizes and surface coatings, and with different incubation times. A high-Resolution laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) time-of-flight (TOF) instrument was applied for imaging the distributions of elements in thin sample sections (20 μm thick). A fibroblast multicellular spheroid (MCS) was selected as the model system and cultured for more than 8 days to produce a natural barrier formed by the extracellular matrix containing collagen. The MCS was then exposed for up to 48 h to one of four types of Ag NPs (∅ 5 nm citrate coated, ∅ 20 nm citrate coated, ∅ 20 nm polyvinylpyrrolidone coated, and ∅ 50 nm citrate coated). Imaging showed that the penetration pathway was strongly related to steric networks formed by collagen fibrils, and Ag NPs with a hydrodynamic diameter of more than 41 nm were completely trapped in an outer rim of the MCSs even after incubation for 48 h. In addition, we examined the impact of these NPs on essential elements (P, Fe, Cu, and Zn) in
areas of Ag NP accumulation. We observed a linear increase at the sub-femtogram level in the total concentration of Cu (fg per pixel) in samples treated with small or large Ag NPs (∅ 5 nm or ∅ 50 nm) for 48 h.
Lead isotopes are a well-established tool to trace the geographic origin of samples and artefacts in archaeology and geochemistry. In archaeology, lead isotopes are often applied to gain information on the provenance of the used ores especially in lead and silver artefacts. The assignment of a specific and unambiguous provenance in most cases is not possible or at least hindered due to several limitations such as ore deposits overlapping in their lead isotopic composition, a large spread within one ore deposit or a missing overlap with known mining sites. Such difficult cases can only be solved by using information from sources being independent of the isotope data. This information can be of chemical nature such as concentrations of key elements or they can be of archaeological nature such as cultural or trade route information.Within this study, we combined lead isotope data of ores and artefacts with silver mass fractions in the ore deposits, Au/Ag-ratios in ores and artefacts and finally archaeological Information on the cultural context in the Mediterranean and Anatolian Region. This approach enabled us to significantly reduce the potential number of mining regions. Finally, the potential sources could be narrowed down to the three remaining locations the Central Taurus, Arap Dağ and the Eastern Troad. Beneath these three locations, the Central Taurus shows the highest probability for the geographic origin of the galena which has been used to create the Trojan silver artefacts.
Rationale: Boron (B) is an essential micronutrient in plants and its isotope variations are used to gain insights into plant metabolism, which is important for crop plant cultivation. B isotope variations were used to trace intra‐plant fractionation mechanisms in response to the B concentration in the irrigation water spanning the
range from B depletion to toxic levels.
Methods: A fully validated analytical procedure based on multi‐collector inductively coupled plasma mass spectrometry (MC‐ICP‐MS), sample decomposition and B Matrix separation was applied to study B isotope fractionation. The Validation was accomplished by establishing a complete uncertainty budget and by applying reference materials, yielding expanded measurement uncertainties of 0.8‰ for pure boric acid solutions and ≤1.5‰ for processed samples. With this validated procedure SI traceable B isotope amount ratios were determined in plant reference materials for the first time.
Results: The B isotope compositions of Irrigation water and bell pepper samples suggest passive diffusion of the heavy 11B isotope into the roots during low to high B concentrations while uptake of the light 10B isotope was promoted during B depletion, probably by active processes. A systematic enrichment of the heavy 11B isotope in higher located plant parts was observed (average Δ11Bleaf‐roots = 20.3 ± 2.8‰ (1 SD)), possibly by a facilitated transport of the heavy 11B isotope to growing Meristems by B transporters.
Conclusions: The B isotopes can be used to identify plant metabolism in Response to the B concentration in the irrigation water and during intra‐plant B transfer. The large B isotope fractionation within the plants demonstrates the importance of
biological B cycling for the global B cycle.