TY - JOUR A1 - Keller, Julia A1 - Moldenhauer, Daniel A1 - Byrne, L. A1 - Haase, H. A1 - Resch-Genger, Ute A1 - Koch, Matthias T1 - Complexes of the mycotoxins citrinin and ochratoxin A with aluminum ions and their spectroscopic properties N2 - The sensitive detection of the mycotoxin citrinin (CIT) utilizing ist fluorescence requires approaches to enhance the emission. In this respect, we studied the complexation of CIT and ochratoxin A (OTA) with Al3+ in methanol using absorption and fluorescence spectroscopy. In this context, an isocratic high performance liquid chromatography (HPLC) method using a polymer column and a fluorescence detector was also developed that enables the separation of the metal ion complexes from the free ligands and non-complexed Al3+. CIT and OTA showed distinct changes in their absorption and fluorescence properties upon Al3+-coordination, and the fluorescence of CIT was considerably enhanced. Analysis of the photometrically assessed titration of CIT and OTA with Al3+ using the Job plot method revealed 1:2 and 1:1 stoichiometries for the Al3+ complexes of CIT (Al:CIT) and OTA (Al:OTA), respectively. In the case of CIT, only one -diketone moiety participates in Al3+ coordination. These findings can be elegantly exploited for signal amplification and provide the base to reduce the limit of detection for CIT quantification by about an order of magnitude, as revealed by HPLC measurements using a fluorescence detector. KW - Complexation KW - Aluminum KW - Fluorescence KW - Job plot KW - HPLC-DAD/FLD PY - 2018 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-470502 DO - https://doi.org/10.3390/toxins10120538 SN - 2072-6651 VL - 10 IS - 12 SP - 538, 1 EP - 8 PB - MDPI CY - Basel AN - OPUS4-47050 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Trog, S. A1 - El-Khatib, Ahmed A1 - Beck, S. A1 - Makowski, M. A1 - Jakubowski, Norbert A1 - Linscheid, M. T1 - Complementarity of molecular and elemental mass spectrometric imaging of Gadovist™ in mouse tissues N2 - Drug biodistribution analyses can be considered a key issue in pharmaceutical discovery and development. Here, mass spectrometric imaging can be employed as a powerful tool to investigate distributions of drug compounds in biologically and medically relevant tissue sections. Both matrix-assisted laser desorption ionization–mass spectrometric imaging as molecular method and laser ablation inductively coupled plasma–mass spectrometric imaging as elemental detection method were applied to determine drug distributions in tissue thin sections. Several mouse organs including the heart, kidney, liver, and brain were analyzed with regard to distribution of Gadovist™, a gadolinium-based contrast agent already approved for clinical investigation. This work demonstrated the successful detection and localization of Gadovist™ in several organs. Furthermore, the results gave evidence that gadolinium-based contrast agents in general can be well analyzed by mass spectrometric imaging methods. In conclusion, the combined application of molecular and elemental mass spectrometry could complement each other and thus confirm analytical results or provide additional information. KW - Laser ablation inductively coupled plasma–mass spectrometry imaging (LA-ICP-MSI) KW - Gadolinium-based contrast agents (GBCAs) KW - Matrix-assisted laser desorption ionization–mass spectrometry imaging (MALDI-MSI) PY - 2019 DO - https://doi.org/10.1007/s00216-018-1477-9 SN - 1618-2642 SN - 1618-2650 VL - 411 IS - 3 SP - 629 EP - 637 PB - Springer AN - OPUS4-47371 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Hantschke, Luisa Lamberta A1 - Steuernagel, Maximilian A1 - Westphalen, Tanja A1 - Kluge, Stephanie A1 - Kaminski, Katja A1 - Piechotta, Christian T1 - Comparison of three different TOP-Assay approaches for the determination of PFAS concentration in soil N2 - Per- and polyfluoroalkyl substances (PFAS) are a large, ever-growing and widely used class of chemicals. Due to the strength of the C-F bond, they do not decompose but accumulate in the environment posing a risk for nature and humans alike. While the use of some PFAS, like perfluorooctanoic acid (PFOA) is already regulated in the EU, new ‘precursor’ substances are used to replace them. However, these precursors may be equally harmful to the environment. In recent years, many ‘hot spot’ sites with high PFAS contaminations in soil have been distinguished, but no German-wide background values have been determined yet. Knowing these background values is crucial to understand the degree of PFAS contamination, underpinning future regulatory decisions. Due to the complexity and variety of different PFAS compounds, one needs to apply a broad spectrum of different techniques to capture most of the PFAS content in one sample. In the framework of this project, 600 soil samples are taken at different sites all over Germany. The concentration of 30 PFAS - 13 carboxylic acids (C4-C18), 5 sulfonic acids (C4-C10) and 12 precursor substances) - is determined in these soil samples using three different sample preparation approaches: 1) ultrasonic extraction of the soil samples with Methanol; 2) preparation of eluates to test the leaching behaviour of the PFAS and 3) TOP assays following the method published by Houtz & Sedlak. Targeted LC-MS/MS is used to determine PFAS concentration after all three preparation steps. For the TOP-assay, the concentration of all 30 PFAS is compared prior to and after the oxidation reaction. Besides the ‘classic’ TOP-Assay, two other TOP-Assay approaches, the dTOP Assay and the photoTOP-Assay, are tested and the results of all three approaches are compared. First, all three TOP-Assay approaches will be tested on a reference soil spiked with a solution including all 30 PFAS measured in the project. Later, soil samples taken in the frame of the priorly described project will be tested. This poster will focus on the results of the experiments comparing the three different TOP Assay approaches in spiked reference soil. Additionally, some of the results of the other sample preparation methods, extraction and eluate preparation will be presented. T2 - FLUOROS 2023 CY - Idstein, Germany DA - 31.08.2023 KW - PFAS TOP Assay soil contamination PY - 2023 AN - OPUS4-58267 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Chazeau, E. A1 - Fabre, C. A1 - Privat, M. A1 - Godard, A. A1 - Racoeur, C. A1 - Bodio, E. A1 - Busser, B. A1 - Wegner, Karl David A1 - Sancey, L. A1 - Paul, C. A1 - Goze, C. T1 - Comparison of the In Vitro and In Vivo Behavior of a Series of NIR-II-Emitting Aza-BODIPYs Containing Different Water-Solubilizing Groups and Their Trastuzumab Antibody Conjugates N2 - The development of new fluorescent organic probes effective in the NIR-II region is currently a fast-growing field and represents a challenge in the domain of medical imaging. In this study, we have designed and synthesized an innovative series of aza-boron dipyrromethenes emitting in the NIR-II region. We have investigated the effect of different water-solubilizing groups not only on the photophysical properties of the compounds but also on their in vitro and in vivo performance after bioconjugation to the antibody trastuzumab. Remarkably, we discovered that the most lipophilic compound unexpectedly displayed the most favorable in vivo properties after bioconjugation. This underlines the profound influence that the fluorophore functionalization approach can have on the efficiency of the resulting imaging agent. KW - NIR-II KW - In vivo imaging KW - Fluorescence KW - Spectroscopy KW - Antibody conjugates PY - 2024 DO - https://doi.org/10.1021/acs.jmedchem.3c02139 SN - 1520-4804 VL - 67 IS - 5 SP - 3679 EP - 3691 PB - ACS Publications CY - Washington, DC AN - OPUS4-59607 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Ickert, Stefanie A1 - Schwaar, Timm A1 - Springer, A. A1 - Grabarics, M. A1 - Riedel, Jens A1 - Beck, S. A1 - Pagel, K. A1 - Linscheid, M. W. T1 - Comparison of the fragmentation behavior of DNA and LNA single strands and duplexes N2 - DNA and locked nucleic acid (LNA) were characterized as single strands, as well as double stranded DNA-DNA duplexes and DNA-LNA hybrids using tandem mass spectrometry with collision-induced dissociation. Additionally, ion mobility spectrometry was carried out on selected species. Oligonucleotide duplexes of different sequences – bearing mismatch positions and abasic sites of complementary DNA 15-mers – were investigated to unravel general trends in their stability in the gas phase. Single stranded LNA oligonucleotides were also investigated with respect to their gas phase behavior and fragmentation upon collision-induced dissociation. In contrast to the collision-induced dissociation of DNA, almost no base loss was observed for LNAs. Here, backbone cleavages were the dominant dissociation pathways. This finding was further underlined by the need for higher activation energies. Base losses from the LNA strand were also absent in fragmentation experiments of the investigated DNA-LNA hybrid duplexes. While DNA-DNA duplexes dissociated easily into single stranded fragments, the high stability of DNA-LNA hybrids resulted in predominant fragmentation of the DNA part rather than the LNA, while base losses were only observed from the DNA single strand of the hybrid. KW - Oligonucleotide fragmentation KW - Locked nucleic acids KW - Collision induced dissociation (CID) KW - Double strands KW - Ion mobility spectrometry PY - 2019 DO - https://doi.org/10.1002/jms.4344 VL - 54 IS - 5 SP - 402 EP - 411 PB - Wiley AN - OPUS4-47485 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Jakubowski, N. A1 - Borrmann, S. A1 - Recknagel, Sebastian A1 - Roik, Janina A1 - Rickert, F. T1 - Comparison of peristaltic pumps used for sample introduction in Inductively Coupled Plasma-Atomic Emission Spectroscopy (ICP-AES) N2 - In this investigation, two conventional peristaltic pumps are compared with a new pump based on the “easy click” principle using a simultaneous ICP-AES instrument with standard operating conditions. It is found that the figures of merit achieved are quite comparable for all three pumps. Relative standard deviations (RSDs) range between 0.2% and 1.8%, and limits of detection as low as 0.1 μg/L have been achieved , demonstrating that the easy click principle of the new pump does not compromise the analytical figures of merit. KW - ICP-AES KW - Peristaltic pumps KW - ICP-MS PY - 2020 IS - 35 / S4 SP - 6 AN - OPUS4-52020 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Groschke, Matthias A1 - Becker, Roland T1 - Comparison of carrier gases for the separation and quantification of mineral oil hydrocarbon (MOH) fractions using online coupled high performance liquid chromatography-gas chromatography-flame ionisation detection N2 - On-line coupled high performance liquid chromatography-gas chromatography-flame ionisation detection (HPLC-GC-FID) was used to compare the effect of hydrogen, helium and nitrogen as carrier gases on the chromatographic characteristics for the quantification of mineral oil hydrocarbon (MOH) traces in food related matrices. After optimisation of chromatographic parameters nitrogen carrier gas exhibited characteristics equivalent to hydrogen and helium regarding requirements set by current guidelines and standardisation such as linear range, quantification limit and carry over. Though nitrogen expectedly led to greater peak widths, all required separations of standard compounds were sufficient and humps of saturated mineral oil hydrocarbons (MOSH) and aromatic mineral oil hydrocarbons (MOAH) were appropriate to enable quantitation similar to situations where hydrogen or helium had been used. Slightly increased peak widths of individual hump components did not affect shapes and widths of the MOSH and MOAH humps were not significantly affected by the use of nitrogen as carrier gas. Notably, nitrogen carrier gas led to less solvent peak tailing and smaller baseline offset. Overall, nitrogen may be regarded as viable alternative to hydrogen or helium and may even extend the range of quantifiable compounds to highly volatile hydrocarbon eluting directly after the solvent peak. KW - Mineral oil hydrocarobons KW - Food KW - Liquid chromatography KW - Gas chromatography KW - MOSH/MOAH PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-601450 DO - https://doi.org/10.1016/j.chroma.2024.464946 SN - 0021-9673 VL - 1726 SP - 1 EP - 7 PB - Elsevier CY - New York, NY AN - OPUS4-60145 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Büchele, Dominique A1 - Rühlmann, Madlen A1 - Schmid, Thomas A1 - Ostermann, Markus T1 - Comparison between uni- and multivariate data analysis for the determination of nutrients in soils using XRF N2 - Aim of the Federal Institute for Materials Research and Testing (BAM) in the frame of I4S - “Intelligence for Soil” is the characterization of an X-ray fluorescence (XRF) based sensor for robust online-application of arable land.Fast soil mapping for agricultural purpose allows the site-specific optimized introduction of plant essential nutrients like S, K, Ca, and Fe. This is important given that the distribution of minor and trace elements varies widely. The non-destructive and contactless XRF is suitable for rapid in-situ analysis on the field due to minimal sample preparation and simultaneous multi-element analysis. Soils are already considered as a complex matrix due to their wide range of elements in different contents, especially light elements with low atomic numbers (Z<19). Problems by measuring soil samples also arise from heterogeneity of the sample and matrix effects. Large grain size distribution causes strong inhomogeneity and matrix effects occur through physical properties related to high concentration of main components. Matrix-specific calibration strategies for determination of total major and minor plant essential nutrients are particularly important regarding these difficulties. For accurate calibration, data treatment and evaluation must also be considered. Empirical univariate and multivariate data analysis were compared regarding their analytical figures of merit. Using principal component analysis (PCA) it was possible to classify German soils in different groups as sand, clay and silt. A calibration curve was obtained by partial least squares regression (PLSR) and the elemental content of German soils was predicted. Elemental distribution maps for different German arable lands were created and the results compared to reference measurements. The correlation between predicted values and reference values were in good agreement for most major and minor nutrients. T2 - BonaRes Conference CY - Berlin, Germany DA - 26.02.2018 KW - PLSR KW - XRF KW - Soil KW - PCA PY - 2018 AN - OPUS4-45007 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Büchele, Dominique A1 - Rühlmann, Madlen A1 - Ostermann, Markus A1 - Schmid, Thomas T1 - Comparison between uni- and multivariate data Analysis for the determination of nutrients in soils using XRF N2 - As part of the BonaRes research initiative funded by the German Federal Ministry of Education and Research (BMBF), strategies are being developed to use soil as a sustainable resource in the bioeconomy. The interdisciplinary subproject I4S - “Intelligence for soil” - is responsible for the development of an integrated system for site-specific management of soil fertility. For this purpose, a platform is constructed and various sensors are installed. Real-time data will be summarized in models and decision-making algorithms will be used to control fertilization and accordingly improve soil functions. This would allow investigations in close meshed dynamic grid and fast analysis of large areas to generate higher yields. This is important given that the distribution of minor and trace elements varies widely. Aim of the Federal Institute for Materials Research and Testing (BAM) in the frame of I4S is the characterization of an X-ray fluorescence (XRF) based sensor for robust online-analysis of arable land. The non-destructive and contactless XRF is suitable for rapid in-situ analysis on the field due to minimal sample preparation and simultaneous multi-element analysis. Soils are already considered as a complex matrix due to their wide range of elements in different contents, especially light elements with low atomic numbers (Z<19). Problems by measuring soil samples also arise from heterogeneity of the sample and matrix effects. Large grain size distribution causes strong inhomogeneity and matrix effects occur through physical properties related to high concentration of main components. Matrix-specific calibration strategies for determination of total major and minor plant essential nutrients are particularly important regarding these difficulties. For accurate calibration, data treatment and evaluation must also be considered. Univariate and multivariate data analysis were compared regarding their analytical figures of merit. Using principal component analysis (PCA) it was possible to classify German soils in different groups as sand, clay and silt. Calibration models were obtained by partial least squares regression (PLSR) and the content of macro- and micronutrients in German soils was predicted. Elemental distribution maps for different German arable lands were created and the results compared to reference measurements. The correlation between predicted values and reference values were in good agreement for most major and minor nutrients. T2 - ESAS/CANAS CY - Berlin, Germany DA - 20.03.2018 KW - Soil KW - XRF KW - PCA KW - PLSR PY - 2018 AN - OPUS4-45010 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Jaeger, Carsten T1 - Comparing Nontargeted LC-MS Methods by Co-visualizing Linear Dynamic Range and Chemical Coverage N2 - INTRODUCTION Biological and environmental samples contain thousands of small molecule species that all vary in chemical properties and concentration range. Identifying and quantifying all these chemical entities remains a long-term goal in metabolomics and related systems approaches. Due to its broad selectivity, nontargeted LC-MS is usually the method of choice for broad chemical screening. Optimizing nontargeted LC-MS methods, however, is less straightforward than for targeted methods where sensitivity, specificity, linearity etc. serve as well-established performance criteria. We therefore investigated linear dynamic range (LDR) and chemical classification as alternative performance criteria to guide nontargeted method development. EXPERIMENTAL METHODS LDR was defined as the linear portion of a feature’s response curve over multiple concentration levels. Comparing the LDR of features across methods can be expected to be significantly more robust than comparing signal intensities for a single concentration. To determine LDR for all features, a computational workflow was implemented in the R programming language. For estimating the linear portion of a curve, several mathematical approaches including linear, non-linear and piecewise linear regression were evaluated. Chemical classification was based on ClassyFire, which computes chemical classes for a given structure. To avoid false classifications for incorrectly annotated compounds, we took the following statistical approach. For each compound, multiple likely annotation hypotheses were derived using a recently described workflow[2]. All annotation hypotheses were submitted to ClassyFire and obtained classifications were ranked by frequency. The most frequently suggested class was kept for further analysis. Finally, LDR and chemical classes were visualized together on a molecular network, which was constructed using the well-established MS/MS similarity approach. RESULTS AND DISCUSSION For technical validation of the workflow, several hundred curve fits obtained from the different regression models were reviewed visually. Piecewise linear regression performed the most reliably with respect to the heterogeneous curve shapes of ‘real-life’ features. Validation of chemical classification was performed against a compound library, which showed that 90% of ~450 library compounds were correctly classified using the described approach. Two liquid chromatography methods (HILIC, RPC) as well as two electrospray ionization variants (low/high-temperature ESI) applied to urinary metabolomics were exemplarily studied to test the workflow. Molecular network visualization indicated that of all analytical setups, HILIC/high temperature ESI performed best in terms of high LDR achieved over a wide range of compound classes. Despite one order of magnitude lower sensitivity, HILIC/low temperature ESI showed similar chemical coverage, except for organic nitrogen compounds that were underrepresented compared to high-temperature ESI. Both RPC setups were inferior to the HILIC setups in terms of high-LDR features, supporting previous findings for the given matrix. The higher relative representation of benzenoids and lipids in RPC demonstrated that the workflow successfully captured expected selectivity differences between chromatographies. CONCLUSION When comparing nontargeted LC-MS methods for optimization purposes, ideally all available quantitative and qualitative information should be integrated. The present workflow follows this idea. Visualizing LDR and chemical classes of all features on a molecular network quickly indicated differences in method selectivity that were otherwise difficult to spot. As an automated approach, it is easily applied to repeated optimization steps, enabling effective optimization strategies. T2 - EURACHEM Workshop CY - Tartu, Estonia DA - 20.05.2019 KW - Linear dynamic range KW - Liquid chromatography-mass spectrometry KW - Nontargeted approach KW - Method development KW - Chemical coverage PY - 2019 AN - OPUS4-48333 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -