TY - JOUR A1 - Bresch, Harald A1 - Hodoroaba, Vasile-Dan A1 - Schmidt, Alexandra A1 - Rasmussen, K. A1 - Rauscher, H. T1 - Counting Small Particles in Electron Microscopy Images — Proposal for Rules and Their Application in Practice N2 - Electron microscopy (EM) is the gold standard for the characterisation of the morphology (size and shape) of nanoparticles. Visual observation of objects under examination is always a necessary first step in the characterisation process. Several questions arise when undertaking to identify and count particles to measure their size and shape distribution. In addition to challenges with the dispersion and identification of the particles, more than one protocol for counting particles is in use. This paper focuses on precise rules for the counting of particles in EM micrographs, as this influences the measurement accuracy of the number of particles, thus implicitly affecting the size values of the counted particles. We review and compare four different, commonly used methods for counting, which we then apply in case studies. The impact of the selected counting rule on the obtained final particle size distribution is highlighted. One main aim of this analysis is to support the application of a specific, well-defined counting approach in accordance with regulatory requirements to contribute to achieving more reliable and reproducible results. It is also useful for the new harmonised measurement procedures for determining the particle size and particle size distribution of nanomaterials. KW - Nano KW - Particle size distribution KW - Nanoparticle KW - Nanomaterial KW - OECD PY - 2022 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-551891 DO - https://doi.org/10.3390/nano12132238 SN - 2079-4991 VL - 12 IS - 13 SP - 2238 PB - MDPI CY - Basel AN - OPUS4-55189 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kittner, Maria A1 - Kerndorff, A. A1 - Ricking, M. A1 - Bednarz, M. A1 - Obermaier, N. A1 - Lukas, M. A1 - Asenova, M. A1 - Bordós, G. A1 - Eisentraut, Paul A1 - Hohenblum, P. A1 - Hudcova, H. A1 - Humer, F. A1 - István, T. G. A1 - Kirchner, M. A1 - Marushevska, O. A1 - Nemejcová, D. A1 - Oswald, P. A1 - Paunovic, M. A1 - Sengl, M. A1 - Slobodnik, J. A1 - Spanowsky, K. A1 - Tudorache, M. A1 - Wagensonner, H. A1 - Liska, I. A1 - Braun, U. A1 - Bannick, C. G. T1 - Microplastics in the Danube River Basin: A First Comprehensive Screening with a Harmonized Analytical Approach N2 - In this study, carried out within the Joint Danube Survey 4, a comprehensive microplastic screening in the water column within a large European river basin from its source to estuary, including major tributaries, was realized. The objective was to develop principles of a systematic and practicable microplastic monitoring strategy using sedimentation boxes for collection of suspended particulate matter followed by its subsequent analysis using thermal extraction desorption-gas chromatography/mass spectrometry. In total, 18 sampling sites in the Danube River Basin were investigated. The obtained suspended particulate matter samples were subdivided into the fractions of >100 μm and <100 μm and subsequently analyzed for microplastic mass contents. The results showed that microplastics were detected in all samples, with polyethylene being the predominant polymer with maximum contents of 22.24 μg/mg, 3.23 μg/mg for polystyrene, 1.03 μg/mg for styrene-butadiene-rubber, and 0.45 μg/mg for polypropylene. Further, polymers such as different sorts of polyester, polyacrylates, polylactide, and natural rubber were not detected or below the detection limit. Additional investigations on possible interference of polyethylene signals by algae-derived fatty acids were assessed. In the context of targeted monitoring, repeated measurements provide more certainty in the interpretation of the results for the individual sites. Nevertheless, it can be stated that the chosen approach using an integrative sampling and determination of total plastic content proved to be successful. KW - Thermal extraction desorption-gas chromatography/mass spectrometry (TED-GC/MS), monitoring KW - Microplastics KW - River KW - Suspended particulate matter (SPM) KW - Sedimentation box (SB) PY - 2022 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-551444 DO - https://doi.org/10.1021/acsestwater.1c00439 VL - 2 IS - 7 SP - 1174 EP - 1181 PB - ACS Publications AN - OPUS4-55144 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kader, A. A1 - Kaufmann, Jan Ole A1 - Mangarova, D. B. A1 - Moeckel, J. A1 - Brangsch, J. A1 - Adams, L. C. A1 - Zhao, J. A1 - Reimann, C. A1 - Saatz, Jessica A1 - Traub, Heike A1 - Buchholz, R. A1 - Karst, U. A1 - Hamm, B. A1 - Makowski, M. R. T1 - Iron Oxide Nanoparticles for Visualization of Prostate Cancer in MRI N2 - Prostate cancer (PCa) is one of the most common cancers in men. For detection and diagnosis of PCa, non-invasive methods, including magnetic resonance imaging (MRI), can reduce the risk potential of surgical intervention. To explore the molecular characteristics of the tumor, we investigated the applicability of ferumoxytol in PCa in a xenograft mouse model in two different tumor volumes, 500 mm3 and 1000 mm3. Macrophages play a key role in tumor progression, and they are able to internalize iron-oxide particles, such as ferumoxytol. When evaluating T2*-weighted sequences on MRI, a significant decrease of signal intensity between pre- and post-contrast images for each tumor volume (n = 14; p < 0.001) was measured. We, furthermore, observed a higher signal loss for a tumor volume of 500 mm3 than for 1000 mm3. These findings were confirmed by histological examinations and laser ablation inductively coupled plasma-mass spectrometry. The 500 mm3 tumors had 1.5% iron content (n = 14; sigma = 1.1), while the 1000 mm3 tumors contained only 0.4% iron (n = 14; sigma = 0.2). In vivo MRI data demonstrated a correlation with the ex vivo data (R2 = 0.75). The results of elemental analysis by inductively coupled plasma-mass spectrometry correlated strongly with the MRI data (R2 = 0.83) (n = 4). Due to its long retention time in the blood, biodegradability, and low toxicity to patients, ferumoxytol has great potential as a contrast agent for visualization PCa. KW - Imaging KW - Nanoparticle KW - Cancer KW - Iron oxide KW - ICP-MS KW - Magnetic resonance imaging PY - 2022 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-550075 DO - https://doi.org/10.3390/cancers14122909 VL - 14 IS - 12 SP - 1 EP - 13 PB - MDPI CY - Basel, Switzerland AN - OPUS4-55007 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Sieber, M. J. A1 - Wilke, M. A1 - Appelt, O. A1 - Oelze, Marcus A1 - Koch-Müller, M. T1 - Melting relations of Ca–Mg carbonates and trace element signature of carbonate melts up to 9 GPa – A proxy for melting of carbonated mantle lithologies N2 - The most profound consequences of the presence of Ca–Mg carbonates (CaCO3–MgCO3) in the Earth’s upper mantle may be to lower the melting temperatures of the mantle and control the melt composition. Low-degree partial melting of a carbonate-bearing mantle produces CO2-rich, silica-poor melts compositionally imposed by the melting relations of carbonates. Thus, understanding the melting relations in the CaCO3–MgCO3 system facilitates the interpretation of natural carbonate-bearing silicate systems. We report the melting relations of the CaCO3–MgCO3 system and the partition coefficient of trace elements between carbonates and carbonate melt from experiments at high pressure (6 and 9 GPa) and temperature (1300–1800 ◦C) using a rocking multi-anvil press. In the absence of water, Ca–Mg carbonates are stable along geothermal gradients typical of subducting slabs. Ca–Mg carbonates (∼ Mg0.1–0.9Ca0.9–0.1CO3) partially melt beneath mid-ocean ridges and in plume settings. Ca–Mg carbonates melt incongruently, forming periclase crystals and carbonate melt between 4 and 9 GPa. Furthermore, we show that the rare earth element (REE) signature of Group-I kimberlites, namely strong REE fractionation and depletion of heavy REE relative to the primitive mantle, is resembled by carbonate melt in equilibrium with Ca-bearing magnesite and periclase at 6 and 9 GPa. This suggests that the dolomite–magnesite join of the CaCO3–MgCO3 system might be useful to approximate the REE signature of carbonate-rich melts parental to kimberlites. KW - High pressure experiments KW - Laser Ablation PY - 2022 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-561197 DO - https://doi.org/10.5194/ejm-34-411-2022 SN - 0935-1221 VL - 34 IS - 5 SP - 411 EP - 424 PB - Copernicus Publications CY - Göttingen AN - OPUS4-56119 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Langenhan, Jennifer A1 - Jaeger, Carsten A1 - Baum, K. A1 - Simon, M. A1 - Lisec, Jan T1 - A Flexible Tool to Correct Superimposed Mass Isotopologue Distributions in GC‐APCI‐MS Flux Experiments N2 - The investigation of metabolic fluxes and metabolite distributions within cells by means of tracer molecules is a valuable tool to unravel the complexity of biological systems. Technological advances in mass spectrometry (MS) technology such as atmospheric pressure chemical ionization (APCI) coupled with high resolution (HR), not only allows for highly sensitive analyses but also broadens the usefulness of tracer‐based experiments, as interesting signals can be annotated de novo when not yet present in a compound library. However, several effects in the APCI ion source, i.e., fragmentation and rearrangement, lead to superimposed mass isotopologue distributions (MID) within the mass spectra, which need to be corrected during data evaluation as they will impair enrichment calculation otherwise. Here, we present and evaluate a novel software tool to automatically perform such corrections. We discuss the different effects, explain the implemented algorithm, and show its application on several experimental datasets. This adjustable tool is available as an R package from CRAN. KW - Mass Spectrometry KW - Isotopologue Distribution KW - Metabolic Flux KW - R package PY - 2022 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-547318 DO - https://doi.org/10.3390/metabo12050408 VL - 12 IS - 5 SP - 1 EP - 10 PB - MDPI AN - OPUS4-54731 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Jaeger, Carsten A1 - Lisec, Jan T1 - Towards Unbiased Evaluation of Ionization Performance in LC-HRMS Metabolomics Method Development N2 - As metabolomics increasingly finds its way from basic science into applied and regulatory environments, analytical demands on nontargeted mass spectrometric detection methods continue to rise. In addition to improved chemical comprehensiveness, current developments aim at enhanced robustness and repeatability to allow long-term, inter-study, and meta-analyses. Comprehensive metabolomics relies on electrospray ionization (ESI) as the most versatile ionization technique, and recent liquid chromatography-high resolution mass spectrometry (LC-HRMS) instrumentation continues to overcome technical limitations that have hindered the adoption of ESI for applications in the past. Still, developing and standardizing nontargeted ESI methods and instrumental setups remains costly in terms of time and required chemicals, as large panels of metabolite standards are needed to reflect biochemical diversity. In this paper, we investigated in how far a nontargeted pilot experiment, consisting only of a few measurements of a test sample dilution series and comprehensive statistical analysis, can replace conventional targeted evaluation procedures. To examine this potential, two instrumental ESI ion source setups were compared, reflecting a common scenario in practical method development. Two types of feature evaluations were performed, (a) summary statistics solely involving feature intensity values, and (b) analyses additionally including chemical interpretation. Results were compared in detail to a targeted evaluation of a large metabolite standard panel. We reflect on the advantages and shortcomings of both strategies in the context of current harmonization initiatives in the metabolomics field. KW - Mass Spectrometry KW - Non-targeted analysis KW - Method development PY - 2022 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-548065 DO - https://doi.org/10.3390/metabo12050426 VL - 12 IS - 5 SP - 1 EP - 13 PB - MDPI AN - OPUS4-54806 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Steinhäuser, Lorin A1 - Piechotta, Christian A1 - Westphalen, Tanja A1 - Kaminski, Katja T1 - Evaluation, comparison and combination of molecularly imprinted polymer solid phase extraction and classical solid phase extraction for the preconcentration of endocrine disrupting chemicals from representative whole water samples N2 - Estrogens are endocrine disrupting chemicals and of high concerns due to demonstrated harmful effects on the environment and low effect levels. For monitoring and risk assessment, several estrogens were included in the "watch list" of the EU Water Framework Directive which sets very low environmental quality standard (EQS) levels for Estrone (E1) and 17β-Estradiol (E2) of 0.4 ng L−1 and for 17α-Ethinylestradiol (EE2) of 0.035 ng L−1 requiring sensitive detection methods, as well as extensive sample preparation. A sensitive, derivatization-free, isotope dilution calibration HPLC-MS/MS method for a panel of 5 selected estrogens (including the 3 estrogens of the EU WFD watchlist), and a procedure for the reproducible preparation of a representative whole water matrix including mineral water, humic acids and solid particulate matter are presented. These are used in a diligent comparison of classical solid phase extraction (SPE) on hydrophilic-lipophilic balanced (HLB) phase to SPE on an estrogen-specific molecularly imprinted polymer phase (MISPE) for ultra-trace levels of the analytes (1–10 ng L−1). Additionally, a two-step procedure combining HLB SPE disks followed by MISPE is evaluated. The tow-step procedure provides superior enrichment, matrix removal and sample throughput while maintaining comparable recovery rates to simple cartridge SPE. Estimated method quantification limits (MQLs) range from 0.109–0.184 ng L−1 and thus meet EQS-levels for E1 and E2, but not EE2. The representative whole water matrix provides a reproducible comparison of sample preparation methods and lays the foundation for a certified reference material for estrogen analysis. The presented method will serve as the basis for an extended validation study to assess its use for estrogen monitoring in the environment. KW - Estrogens KW - Whole water samples KW - Molecular imprinted polymers KW - EU-WFD PY - 2022 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-563547 DO - https://doi.org/10.1016/j.talo.2022.100163 SN - 2666-8319 VL - 6 SP - 1 EP - 5 PB - Elsevier B.V. CY - Amsterdam, Niederlande AN - OPUS4-56354 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Alcalde-Vasquez, R. A1 - Moreno-Pedraza, A. A1 - Rosas-Román, I. A1 - Guillén-Alonso, H. A1 - Riedel, Jens A1 - Partida-Martínez, L. P. A1 - Winkler, R. T1 - MoBiMS: A Modular Miniature Mass Analyzer for the Real-Time 2 Monitoring of Gases and Volatile Compounds in Biological Systems N2 - Living organisms constantly interact with their environment, including through the exchange of gases. Respiration and the release and uptake of volatile organic compounds (VOCs) create dynamic microenvironments in biological systems. Studying the kinetics of volatiles in biological systems requires expensive instruments, and data analysis is challenging. Therefore, we aimed to design a minimal analytical device for measuring the composition of gaseous mixtures in realtime. We built the ‘Modular Biological Mass Spectrometer’ (MoBiMS) from 3D-printed parts and custom sensors to fit a wide array of experimental set-ups. We tested the chemical detection range and temporal resolution of the MoBiMS employing pure compounds and complex biological samples. Compounds with a higher than 0.4 mmHg vapor pressure and a molecular weight up to 154 g/mol were reliably sensed within seconds. The generated electron impact (EI) spectra were directly comparable with standard databases like the NIST EI library. Under a direct analysis approach, the MoBiMS identified the characteristic odor of banana (Musa sp.), that is, isoamyl acetate; tracked the dynamics of CO2 release while the Alka-Seltzer® reaction occurred showed the kinetics of the transient production and consumption of carbon dioxide during photosynthesis. MoBiMS also discriminated between volatile compounds ions coming from tobacco (Nicotiana benthamiana) leaves and the surrounding air through untargeted analysis. The small footprint of the MoBiMS and its relatively low energy consumption facilitate in situ analyses, as an additional gas supply is not necessary with EI ionization. The MoBiMS is easy to assemble, and its construction and operation are very cost-efficient compared to commercial devices. The analytical performance of the MoBiMS is suitable for real-time studies of biological systems, environmental monitoring, and medical diagnostics. KW - Mass spectrometry KW - Instrumentation KW - Miniaturization KW - Volatiles PY - 2022 DO - https://doi.org/10.1016/j.microc.2021.107090 SN - 0026-265X VL - 175 PB - Elsevier B.V. CY - Amsterdam AN - OPUS4-56528 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - van Wasen, S. A1 - You, Yi A1 - Beck, S. A1 - Riedel, Jens A1 - Volmer, D. A. T1 - Laser Ablation Secondary Electrospray Ionization for In Situ Mass Spectrometric Interrogation of Acoustically-Levitated Droplets N2 - The composition of acoustically levitated droplets was probed by a novel combination of mid-IR laser evaporation and subsequent postionization via secondary electrospray ionization. The combination of microliter samples and subnanoliter sampling provided time-resolved interrogation of droplets and allowed for a kinetic investigation of the laser-induced release of the analyte, which was found to strongly depend on the analytes. The observed substancespecific delayed release of the analytes permitted baseline-separated discrimination of the analytes, ideal for the study of complex samples. The additionally applied postionization scheme was found to enable efficient detection of small volatile compounds as well as peptides. The detection of small molecules and peptides occurred under very different sampling geometries, pointing to two distinct underlying ionization mechanisms. Overall, our results suggest that the experimental setup presented in this study can serve as a widely applicable platform to study chemical reactions in acoustically levitated droplets as model reactors. KW - Acoustic levitation KW - Mass spectrometry KW - Electrospray KW - Laser ablation PY - 2022 DO - https://doi.org/10.1021/acs.analchem.2c03800 SN - 0003-2700 VL - 2022 SP - 1 EP - 5 PB - ACS Publications CY - Washington AN - OPUS4-56531 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Anderhalten, L. A1 - Silva, R. V. A1 - Morr, A. A1 - Wang, S. A1 - Smorodchenko, A. A1 - Saatz, Jessica A1 - Traub, Heike A1 - Mueller, S. A1 - Boehm-Sturm, P. A1 - Rodriguez-Sillke, Y. A1 - Kunkel, D. A1 - Hahndorf, J. A1 - Paul, F. A1 - Taupitz, M. A1 - Sack, I. A1 - Infante-Duarte, C. T1 - Different Impact of Gadopentetate and Gadobutrol on Inflammation-Promoted Retention and Toxicity of Gadolinium Within the Mouse Brain N2 - Objectives: Using a murine model of multiple sclerosis, we previously showed that repeated administration of gadopentetate dimeglumine led to retention of gadolinium (Gd) within cerebellar structures and that this process was enhanced with inflammation. This study aimed to compare the kinetics and retention profiles of Gd in inflamed and healthy brains after application of the macrocyclic Gd-based contrast agent (GBCA) gadobutrol or the linear GBCA gadopentetate. Moreover, potential Gd-induced neurotoxicity was investigated in living hippocampal slices ex vivo. Materials and Methods: Mice at peak of experimental autoimmune encephalomyelitis (EAE; n = 29) and healthy control mice (HC; n = 24) were exposed to a cumulative dose of 20 mmol/kg bodyweight of either gadopentetate dimeglumine or gadobutrol (8 injections of 2.5 mmol/kg over 10 days). Magnetic resonance imaging (7 T) was performed at baseline as well as at day 1, 10, and 40 post final injection (pfi) of GBCAs. Mice were sacrificed after magnetic resonance imaging and brain and blood Gd content was assessed by laser ablation-inductively coupled plasma (ICP)-mass spectrometry (MS) and ICP-MS, respectively. In addition, using chronic organotypic hippocampal slice cultures, Gd-induced neurotoxicity was addressed in living brain tissue ex vivo, both under control or inflammatory (tumor necrosis factor α [TNF-α] at 50 ng/μL) conditions. Results: Neuroinflammation promoted a significant decrease in T1 relaxation times after multiple injections of both GBCAs as shown by quantitative T1 mapping of EAE brains compared with HC. This corresponded to higher Gd retention within the EAE brains at 1, 10, and 40 days pfi as determined by laser ablation-ICP-MS. In inflamed cerebellum, in particular in the deep cerebellar nuclei (CN), elevated Gd retention was observed until day 40 after last gadopentetate application (CN: EAE vs HC, 55.06 ± 0.16 μM vs 30.44 ± 4.43 μM). In contrast, gadobutrol application led to a rather diffuse Gd content in the inflamed brains, which strongly diminished until day 40 (CN: EAE vs HC, 0.38 ± 0.08 μM vs 0.17 ± 0.03 μM). The analysis of cytotoxic effects of both GBCAs using living brain tissue revealed an elevated cell death rate after incubation with gadopentetate but not gadobutrol at 50 mM. The cytotoxic effect due to gadopentetate increased in the presence of the inflammatory mediator TNF-α (with vs without TNF-α, 3.15% ± 1.18% vs 2.17% ± 1.14%; P = 0.0345). Conclusions: In the EAE model, neuroinflammation promoted increased Gd retention in the brain for both GBCAs. Whereas in the inflamed brains, efficient clearance of macrocyclic gadobutrol during the investigated time period was observed, the Gd retention after application of linear gadopentetate persisted over the entire observational period. Gadopentetate but not gadubutrol appeared to be neurotoxic in an ex vivo paradigm of neuronal inflammation. KW - Imaging KW - ICP-MS KW - Gadolinium KW - Contrast agent KW - Laser ablation KW - Brain KW - Multiple sclerosis PY - 2022 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-546910 DO - https://doi.org/10.1097/RLI.0000000000000884 SN - 0020-9996/22/0000–0000 VL - 57 IS - 10 SP - 677 EP - 688 PB - Wolters Kluwer N.V. CY - Alphen aan den Rijn, The Netherlands AN - OPUS4-54691 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Martins, Ines A1 - Al-Sabbagh, Dominik A1 - Bentrup, U. A1 - Marquardt, Julien A1 - Schmid, Thomas A1 - Scoppola, E. A1 - Kraus, Werner A1 - Stawski, Tomasz A1 - de Oliveira Guilherme Buzanich, Ana A1 - Yusenko, Kirill A1 - Weidner, Steffen A1 - Emmerling, Franziska T1 - Formation Mechanism of a Nano-Ring of Bismuth Cations and Mono-Lacunary Keggin-Type Phosphomolybdate N2 - A new hetero-bimetallic polyoxometalate (POM) nano-ring was synthesized in a one-pot procedure. The structure consists of tetrameric units containing four bismuth-substituted monolacunary Keggin anions including distorted [BiO8] cubes. The nano-ring is formed via self-assembly from metal precursors in aqueous acidic medium. The compound (NH4)16[(BiPMo11O39)4] ⋅ 22 H2O; (P4Bi4Mo44) was characterized by single-crystal X-ray diffraction, extended X-ray absorption fine structure spectroscopy (EXAFS), Raman spectroscopy, matrix-assisted laser desorption/ionisation-time of flight mass spectrometry (MALDI-TOF), and thermogravimetry/differential scanning calorimetry mass spectrometry (TG-DSC-MS). The formation of the nano-ring in solution was studied by time-resolved in situ small- and wide-angle X-ray scattering (SAXS/WAXS) and in situ EXAFS measurements at the Mo−K and the Bi−L3 edge indicating a two-step process consisting of condensation of Mo-anions and formation of Bi−Mo-units followed by a rapid self-assembly to yield the final tetrameric ring structure. KW - Bismuth KW - In situ EXAFS KW - In situ SAXS/WAXS KW - Lacunary Keggin ion KW - Polyoxometalates KW - Self-assembly PY - 2022 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-546823 DO - https://doi.org/10.1002/chem.202200079 SN - 0947-6539 VL - 28 IS - 27 SP - 1 EP - 7 PB - Wiley-VCH CY - Weinheim AN - OPUS4-54682 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Knoche, Lisa A1 - Lisec, Jan A1 - Schwerdtle, T. A1 - Koch, Matthias T1 - LC-HRMS-Based Identification of Transformation Products of the Drug Salinomycin Generated by Electrochemistry and Liver Microsome N2 - The drug salinomycin (SAL) is a polyether antibiotic and used in veterinary Medicine as coccidiostat and growth promoter. Recently, SAL was suggested as a potential anticancer drug. However, transformation products (TPs) resulting from metabolic and environmental degradation of SAL are incompletely known and structural information is missing. In this study, we therefore systematically investigated the formation and identification of SAL derived TPs using electrochemistry (EC) in an electrochemical reactor and rat and human liver microsome incubation (RLM and HLM) as TP generating methods. Liquid chromatography (LC) coupled to high-resolution mass spectrometry (HRMS) was applied to determine accurate masses in a suspected target analysis to identify TPs and to deduce occurring modification reactions of derived TPs. A total of 14 new, structurally different TPs were found (two EC-TPs, five RLM-TPs, and 11 HLM-TPs). The main modification reactions are decarbonylation for EC-TPs and oxidation (hydroxylation) for RLM/HLM-TPs. Of particular interest are potassium-based TPs identified after liver microsome incubation because these might have been overlooked or declared as oxidated sodium adducts in previous, non-HRMS-based studies due to the small mass difference between K and O + Na of 21 mDa. The MS fragmentation pattern of TPs was used to predict the position of identified modifications in the SAL molecule. The obtained knowledge regarding transformation reactions and novel TPs of SAL will contribute to elucidate SAL-metabolites with regards to structural prediction. KW - Salinomycin KW - Ionophore antibiotics KW - Transformation product KW - Electrochemistry KW - Rat/human liver microsomes KW - HRMS PY - 2022 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-542543 DO - https://doi.org/10.3390/antibiotics11020155 SN - 2079-6382 VL - 11 IS - 2 SP - 155 PB - MDPI CY - Basel AN - OPUS4-54254 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Boyraz, B. A1 - Saatz, Jessica A1 - Pompös, I.-M. A1 - Gad, Michel A1 - Dernedde, J. A1 - Maier, A.-M. B. A1 - Moscovitz, O. A1 - Seeberger, P. H. A1 - Traub, Heike A1 - Tauber, R. T1 - Imaging Keratan Sulfate in Ocular Tissue Sections by Immunofluorescence Microscopy and LA-ICP-MS N2 - Carbohydrate-specific antibodies can serve as valuable tools to monitor alterations in the extracellular matrix resulting from pathologies. Here, the keratan sulfate-specific monoclonal antibody MZ15 was characterized in more detail by immunofluorescence microscopy as well as laser ablation ICP-MS using tissue cryosections and paraffin-embedded samples. Pretreatment with keratanase II prevented staining of samples and therefore demonstrated efficient enzymatic keratan sulfate degradation. Random fluorescent labeling and site-directed introduction of a metal cage into MZ15 were successful and allowed for a highly sensitive detection of the keratan sulfate landscape in the corneal stroma from rats and human tissue. KW - Laser ablation KW - Imaging KW - Glycosaminoglycan KW - ICP-MS KW - Immunohistochemistry KW - Immunofluorescence KW - Tissue PY - 2022 DO - https://doi.org/10.1021/acsabm.1c01240 VL - 5 IS - 2 SP - 853 EP - 861 PB - American Chemical Society CY - Washington AN - OPUS4-54341 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Casali, C. A1 - Feiler, Torvid A1 - Heilmann, Maria A1 - Braga, D. A1 - Emmerling, Franziska A1 - Grepioni, F. T1 - Too much water? Not enough? In situ monitoring of the mechanochemical reaction of copper salts with dicyandiamide N2 - n situ monitoring of mechanochemical reactions between dicyandiamide (DCD) and CuX2 salts (X = Cl−, NO3−), for the preparation of compounds of agrochemical interest, showed the appearance of a number of phases. It is demonstrated that milling conditions, such as the amount of water added in wet grinding and/or the milling frequency, may affect the course of the mechanochemical reactions, and drive the reaction towards the formation of different products. It has been possible to discover by in situ monitored experiments two novel crystalline forms, namely the neutral complexes [Cu(DCD)2(OH2)2(NO3)2] (2) and [Cu(DCD)2(OH2)Cl2]·H2O (4), in addition to the previously known molecular salt [Cu(DCD)2(OH2)2][NO3]2·2H2O (1, DIVWAG) and neutral complex [Cu(DCD)2(OH2)Cl2] (3, AQCYCU), for which no synthesis conditions were available. Compounds 2 and 4 were fully characterized via a combination of solid-state techniques, including X-ray diffraction, Raman spectroscopy and TGA. KW - Mechanochemistry KW - In situ PY - 2022 DO - https://doi.org/10.1039/d1ce01670a VL - 24 IS - 6 SP - 1292 EP - 1298 PB - RSC AN - OPUS4-54344 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Simon, Fabian A1 - Gehrenkemper, Lennart A1 - von der Au, Marcus A1 - Wittwer, Phillip A1 - Roesch, Philipp A1 - Pfeifer, Jens A1 - Cossmer, Antje A1 - Meermann, Björn T1 - A fast and simple PFAS extraction method utilizing HR–CS–GFMAS for soil samples N2 - Here, we describe an optimized fast and simple extraction method for the determination of per- and polyfluorinated alkyl substances (PFASs) in soils utilizing high resolution-continuum source-graphite furnace molecular absorption spectrometry (HR–CS–GFMAS). To omit the bias of the solid phase extraction (SPE) step commonly used during the analysis of extractable organically bound fluorine (EOF) we optimized a fast and simple SPE-free extraction method. The developed extraction method consists of a liquid-solid extraction using acidified methanol without any additional SPE. Four extraction steps were representative to determine a high proportion of the EOF (>80% of eight extractions). Comparison of the optimized method with and without an additional SPE clean-up step revealed a drastic underestimation of EOF concentrations using SPE. Differences of up to 94% were observed which were not explainable by coextracted inorganic fluoride. Therefore, not only a more accurate but also a more economic as well as ecologic method (bypassing of unnecessary SPE) was developed. The procedural limit of quantification (LOQ) of the developed method was 10.30 μg/kg which was sufficient for quantifying EOF concentrations in all tested samples. For future PFAS monitoring and potential regulative decisions the herein presented optimized extraction method can offer a valuable contribution. KW - Per- and polyfluorinated alkly substances (PFASs) KW - High resolution-continuum source-graphite furnace molecular absorption spectrometry (HR-CS-GFMAS) KW - Soils KW - Solid phase extraction (SPE) KW - Extractable organically bound fluorine (EOF) KW - Solid-liquid extraction PY - 2022 DO - https://doi.org/10.1016/j.chemosphere.2022.133922 VL - 295 SP - 1 EP - 9 PB - Elsevier Ltd. AN - OPUS4-54359 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Frisch, M. A1 - Raza, M. H. A1 - Ye, M.-Y. A1 - Sachse, René A1 - Paul, B. A1 - Gunder, R. A1 - Pinna, N. A1 - Kraehnert, R. T1 - ALD-coated mesoporous iridium-titanium mixed oxides: Maximizing iridium utilization for an outstanding OER performance N2 - With the increasing production of renewable energy and concomitant depletion of fossil resources, the demand for efficient water splitting electrocatalysts continues to grow. Iridium (Ir) and iridium oxides (IrOₓ) are currently the most promising candidates for an efficient oxygen evolution reaction (OER) in acidic medium, which remains the bottleneck in water electrolysis. Yet, the extremely high costs for Ir hamper a widespread production of hydrogen (H₂) on an industrial scale. Herein, the authors report a concept for the synthesis of electrode coatings with template-controlled mesoporosity surface-modified with highly active Ir species. The improved utilization of noble metal species relies on the synthesis of soft-templated metal oxide supports and a subsequent shape-conformal deposition of Ir species via atomic layer deposition (ALD) at two different reaction temperatures. The study reveals that a minimum Ir content in the mesoporous titania-based support is mandatory to provide a sufficient electrical bulk conductivity. After ALD, a significantly enhanced OER activity results in dependency of the ALD cycle number and temperature. The most active developed electrocatalyst film achieves an outstanding mass-specific activity of 2622 mA mg(Ir)⁻¹ at 1.60 V(RHE) in a rotating-disc electrode (RDE) setup at 25 °C using 0.5 m H₂SO₄ as a supporting electrolyte. KW - Acidic oxygen evolution reaction KW - Atomic layer deposition KW - Electrocatalysis KW - Iridium oxide KW - Soft-templated mesoporous films PY - 2022 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-542651 DO - https://doi.org/10.1002/admi.202102035 SN - 2196-7350 SP - 1 EP - 11 PB - Wiley-VCH CY - Weinheim AN - OPUS4-54265 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Munir, R. A1 - Lisec, Jan A1 - Swinnen, J. V. A1 - Zaidi, N. T1 - Too complex to fail? Targeting fatty acid metabolism for cancer therapy N2 - Given the central role of fatty acids in cancer pathophysiology, the exploitation of fatty acid metabolism as a potential antineoplastic therapy has gained much attention. Several natural and synthetic compounds targeting fatty acid metabolism were hitherto identified, and their effectiveness against cancer cell proliferation and survival was determined. This review will discuss the most clinically viable inhibitors or drugs targeting various proteins or enzymes mapped on nine interconnected fatty acid metabolism-related processes. We will discuss the general significance of each of these processes and the effects of their inhibition on cancer cell progression. Moreover, their mechanisms of action, limitations, and future perspectives will be assessed. KW - Fatty acids KW - Fatty acid synthesis KW - Fatty acid desaturation KW - Fatty acid uptake KW - Cancer therapy PY - 2022 DO - https://doi.org/10.1016/j.plipres.2021.101143 SN - 0163-7827 VL - 85 SP - 1 EP - 12 PB - Elsevier AN - OPUS4-53864 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Sommerfeld, Thomas A1 - Jung, Christian A1 - Riedel, Juliane A1 - Mauch, Tatjana A1 - Sauer, Andreas A1 - Koch, Matthias T1 - Development of a certified reference material for the determination of polycyclic aromatic hydrocarbons (PAHs) in rubber toy N2 - Polycyclic aromatic hydrocarbons (PAHs) are a large group of priority organic pollutants, which contaminate environmental compartments, food, and consumer products as well. Due to their frequent occurrence associated with elevated Levels of PAHs, plastic and rubber parts of consumer products and toys are particular sources of exposure. Although European maximum levels exist for eight carcinogenic PAHs in consumer products and toys according to REACH Regulation (EC) No. 1907/2006, certified reference materials (CRM) are still not available. To overcome this lack, the first CRM for the determination of PAHs in rubber toys (BAM-B001) was developed according to the requirements of ISO Guide 35. The whole process of CRM development including preparation, homogeneity and stability studies, and value assignment is presented. The assignment of the certified mass fractions was based upon in-house study at BAM using stable isotope Dilution analysis (SIDA) gas chromatography mass spectrometry (GC–MS). The obtained values were confirmed by the results of two interlaboratory comparison (ILC) studies with more than 50 expert laboratories from Germany and China. The mass fractions of 14 PAHs including all REACH and GS mark regulated compounds were certified ranging between 0.2 and 15.4 mg/ kg accompanied by expanded uncertainties (coverage factor k = 2). In addition, informative values were determined for 4 PAHs, mainly due to higher uncertainties and/or lack of ILC data for confirmation. BAM-B001 is intended for analytical quality control particularly based on the AfPS GS 2019:01 PAK method and contributes to improve the chemical safety of consumer products including toys. KW - PAHs KW - Consumer Products KW - Toys KW - Chemical Safety KW - Certified reference material KW - Quality assurance PY - 2021 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-539920 DO - https://doi.org/10.1007/s00216-021-03796-5 VL - 414 IS - 15 SP - 4369 EP - 4378 PB - Springer AN - OPUS4-53992 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Sebald, M. A1 - Gebauer, J. A1 - Koch, Matthias T1 - Diastereoselective synthesis of (±)-trichodiene and (±)-trichodiene-D3 as analytical standards for the on-site quantification of trichothecenes N2 - The ubiquitous Fusarium genus is responsible for the spoilage of vast amounts of cereals and fruits. Besides the economic damage, the danger to human and animal health by the concomitant exposure to mycotoxins represents a serious problem. A large number of Fusarium species produce a variety of different mycotoxins of which the class of trichothecenes are of particular importance due to their toxicity. Being identified as the common volatile precursor during the biosynthesis of trichothecenes, (−)-trichodiene (TD) is considered to be a biomarker for the respective mycotoxin content in food samples. We postulated that the development of a non-invasive, on-site GC-IMS method for the quantification of (−)-trichodiene supplemented with a stationary SIDA headspace GC-MS reference method would allow circumventing the laborious and expensive analyses of individual trichothecenes in large cereal samples. In this work we present the syntheses of the required native calibration standard and an isotope labeled (TD-D3) internal standard. KW - Mycotoxins KW - Volatile marker KW - Food analysis KW - Screening method KW - Mobile analysis PY - 2021 DO - https://doi.org/10.1039/d1ob01778k VL - 19 IS - 45 SP - 9872 EP - 9879 PB - RSC AN - OPUS4-53993 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Sebald, M. A1 - Gebauer, J. A1 - Koch, Matthias T1 - Concise Synthesis of Alternariol and Alternariol-9-monomethyl ether as well as their D3-Isotopologues N2 - Abstract Alternariol (AOH) and alternariol-9-monomethyl ether (AME) are two secondary metabolites of Alternaria fungi which can be found in various foodstuff like tomatoes, nuts, and grains. Due to their toxicity and potential mutagenic activity the need for the development of high-throughput methods for the supervision of AOH- and AME-levels is of increasing interest. As the availability of both native and labeled AOH and AME analytical standards is very limited we herein wish to present a novel concise approach towards their synthesis employing a ruthenium-catalyzed ortho-arylation as the key step. Finally, we demonstrate their suitability as internal standards in stable-isotope dilution assay (SIDA)-HPLC-MS/MS analysis commonly used for the quantification of the natural products in food and feed. KW - Mycotoxins KW - Food Analysis KW - Emerging contaminants PY - 2021 DO - https://doi.org/10.1055/a-1698-8328 SN - 0039-7881 VL - 54 IS - 19 SP - 4285 EP - 4293 PB - Thieme AN - OPUS4-53994 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -