TY - CONF A1 - Riedel, Soraya A1 - Schneider, Rudolf T1 - Smartphone-based amperometric detection of 3,3′,5,5′-tetramethylbenzidine (TMB) – An immunomagnetic Ochratoxin A assay N2 - 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. Since it is well-known that oxidized TMB can precipitate on electrode surfaces[2], we have studied pitfalls of the electrochemical detection of TMB. By cyclic voltammetry we have compared the stability of the electrochemistry of TMB at different electrode materials (gold and carbon) and pH values (pH 1 and pH 4). It was found that a stable response of the electrode could be achieved at pH 1 on gold electrodes. Thus, we applied these reaction conditions for amperometric detection of TMB in the OTA assay. 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. T2 - European Biosensor Symposium 2021 CY - Online meeting DA - 09.03.2021 KW - Ochratoxin A KW - Cyclic voltammetry KW - Amperometry KW - Smartphone KW - Immunoassay PY - 2021 N1 - Geburtsname von Riedel, Soraya: Höfs, S. - Birth name of Riedel, Soraya: Höfs, S. AN - OPUS4-52269 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Langenhan, Jennifer A1 - Lisec, Jan A1 - Jaeger, Carsten T1 - PEGs in the human body: where they are coming from and what they are doing N2 - The general understanding has been that PEGs are biologically inert, meaning they pass the human body without any relevant reaction with anything. But recent studies have shown that migth not be correct. Here a retrospective analysis of LC-MS data was performed to determine correlations between blood PEG levels in humans and different experimental factors. T2 - Make and Measure 2021 CY - Online meeting DA - 16.09.2021 KW - PEG KW - Polyethylene glycole KW - Retrospective analysis PY - 2021 AN - OPUS4-53391 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Riedel, Soraya A1 - Hülagü, Deniz A1 - Bennet, Francesca A1 - Carl, Peter A1 - Flemig, Sabine A1 - Schmid, Thomas A1 - Schenk, Jörg A1 - Hodoroaba, Vasile-Dan A1 - Schneider, Rudolf T1 - Steps Forward in the Application of 3,3’,5,5’- Tetramethylbenzidine (TMB) in Amperometric Assays N2 - Electrochemical methods make great promise to meet the demand for user-friendly on-site devices for monitoring important parameters. Food industry often runs own lab procedures, e.g. for mycotoxin analysis, but it is a major goal to simplify analysis, linking analytical methods with miniaturized technologies. Enzyme-linked immunosorbent assays, with photometric detection of the horseradish peroxidase (HRP) substrate, 3,3’,5,5’-tetramethylbenzidine (TMB), form a good basis for sensitive detection. To provide a straight-forward approach for the miniaturization of the detection step, we have studied the pitfalls of the electrochemical TMB detection. By cyclic voltammetry it was found that the TMB electrochemistry is strongly dependent on the pH and the electrode material. It was found that screen-printed gold electrodes and a highly acidic pH value (pH 1) are well-suited to perform the electrochemical detection of TMB, due to the reversible character of the redox reaction under these conditions. This set-up provides a good signal stability over several measuring cycles, providing the basis for analysing multiple samples. In contrast to this, for carbon screen-printed electrodes, it was found that the signal response has changed after the electrochemical reaction with TMB at pH 1. At a weakly acidic pH value (pH 4), neither with carbon nor with gold electrodes a reproducible electrochemical detection of TMB could be achieved [1]. Based on these findings we created a smartphone-based, electrochemical, immunomagnetic assay for the detection of ochratoxin A and ergometrine in real samples. Therefore, a competitive assay was performed on magnetic beads using HRP and TMB/H2O2 to generate the signal. Enzymatically oxidized TMB was quantified after addition of H2SO4 by amperometry with screen-printed gold electrodes in a custom-made wall-jet flow cell. The results are in good correlation with the established photometric detection method, providing a solid basis for sensing of further analytes in HRP-based assays using the newly developed miniaturized smartphone-based, electrochemical, immunomagnetic assay. T2 - Electrochemistry 2022 CY - Berlin, Germany DA - 28.09.2022 KW - Cylic Voltammetry KW - Immunoassay KW - TMB KW - Amperometry PY - 2022 N1 - Geburtsname von Riedel, Soraya: Höfs, S. - Birth name of Riedel, Soraya: Höfs, S. AN - OPUS4-55876 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Ecke, Alexander A1 - Westphalen, Tanja A1 - Retzmann, Anika A1 - Schneider, Rudolf T1 - The Fate of the Antibiotic Amoxicillin in the Aquatic Environment N2 - Contamination of the environment with antibiotics is of great concern as it promotes the evolution of antimicrobial resistances. In case of amoxicillin (AMX) in the aquatic environment, further risk arises from hydrolysis products (HPs) which can cause allergy. To assess these risks, a comprehensive investigation and understanding of the degradation of AMX is necessary. We investigated the hydrolysis rate of AMX in different types of water as well as the influence of temperature and irradiation. The content of the heavy metal ions copper and zinc was found to be crucial for the hydrolysis rate of AMX and stability of HPs. Eventually, a new degradation pathway for AMX could be elaborated and confirmed by tandem mass spectrometry (LC-MS/MS). T2 - Berliner Chemie in Praxis Symposium CY - Berlin, Germany DA - 07.10.2022 KW - Hydrolysis KW - Amoxicillin KW - LC-MS/MS KW - ICP-MS PY - 2022 AN - OPUS4-56026 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Piechotta, Christian A1 - Steinhäuser, Lorin A1 - Lardy-Fontan, S. A1 - Lalere, B. A1 - Le Diouron, V. A1 - Heath, E. A1 - Ana Kovačič, A. A1 - Potalivo, M. A1 - de Zorzi, P. A1 - Centioli, D. A1 - Naykki, T. A1 - Viidanoja, J. A1 - Gökcen, T. A1 - Budzinski, H. A1 - Le Menach, K. A1 - Selih, V. T1 - EDC-WFD: A project to deliver reliable measurements for better monitoring survey and risks assessments. N2 - 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 (17E2) and estriol (E3) will be included to demonstrate the reliability of the developed methods 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 selected effect-based methods (EBM) will be deeply investigated in order to improve their rationale use and their support in water quality assessment. In particular, the EBM sensitivity, specificity and accuracy on reference materials with single or mixture solutions of the five substances at a concentration of EQS values will be explored. This contribution will present the objectives and methods applied within the EDC-WFD project. T2 - EuChemS CY - Lisbon, Portugal DA - 29.08.2022 KW - WFD KW - Estrogens KW - Whole water samples KW - EQS PY - 2022 AN - OPUS4-57096 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Piechotta, Christian A1 - Kovačič, A. A1 - Steinhäuser, Lorin A1 - Heath, E. A1 - Lardy-Fontan, S. T1 - A method for monitoring estrogens in whole surface waters by GC-MS/MS N2 - Natural and synthetic estrogens are key endocrine-disrupting chemicals. Despite occurring at ultra-trace levels (below ng L-1), it is believed that they are contributing to an increase in feminized fish and other endocrine disruptive effects, and hence, their inclusion in the Watch list was not unexpected. One of the main sources ofestrogens to surface waters is wastewater effluent. Once in surface waters, they can partition into different compartments, i.e., water and suspended particulate matter. For this reason, there is an urgent need for a methodology to monitor estrogen levels below the environmental quality standards (EQS) set by the Water Framework Directive requirements. In this study, a precise and accurate gas chromatography-mass spectrometry method (GC-MS/MS) for the analysis of estrone (E1), 17β-estradiol (17β-E2), 17α-estradiol (17α- E2), 17-alpha-ethinylestradiol (EE2), and estriol (E3) in whole water samples with ng L-1 limit of quantification (LOQ) was developed and validated in accordance with CEN/TS 16800:2020 guidelines. T2 - IMSC 2022 CY - Maastricht, Netherlands DA - 27.08.2022 KW - EDC KW - WFD KW - GC-MS PY - 2022 AN - OPUS4-57097 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Almeida, Â. A1 - Freitas, R. A1 - Calisto, V. A1 - Esteves, V. I. A1 - Schneider, Rudolf A1 - Soares, A. M. V. M. A1 - Figueira, E. A1 - Campos, B. A1 - Barata, C. T1 - Pharmaceutical drugs under an ocean acidification scenario: the biochemical and transcriptomic effects on the clam Ruditapes philippinarum N2 - Carbamazepine (CBZ) and cetirizine (CTZ) are pharmaceutical drugs detected in the aquatic environment. However, the effects to marine invertebrates derived from the combination of these drugs with decreased pH conditions due to ocean acidification are poorly explored. This study investigated the biochemical parameters related to metabolic capacity and oxidative stress response and the transcription of genes related to the mode of action (MoA) of CBZ (1.0 μg/L) and CTZ (0.6 μg/L) in the clam Ruditapes philippinarum chronically exposed (28 days) to control (7.8) and low (7.5) pH conditions. The biochemical parameters applied were: the activity of electron transport system (indicator of organisms’ metabolic capacity); lipid peroxidation content (indicator of cell damage); total glutathione peroxidase activity (indicator of antioxidant defense). The transcription of genes related with drug neurotransmission and metabolism, cell defense and immunity and biomineralization was studied. No metabolic changes and oxidative stress was induced by the exposure to CBZ or CTZ at each pH level, but the transcription of several genes related with the MoA (neurotransmission, immunity and biomineralization) was altered by low pH, drug exposure and the combination of both stressors. In conclusion, it was shown that the interaction of drug exposure and low pH conditions can change bivalves’ sensitivity to drugs or alter drugs toxicity. T2 - 31st Congress of the New European Society for Comparative Physiology and Biochemistry ESCPB CY - Porto, Portugal DA - 09.09.2018 KW - Pharmaceutical Drugs KW - Climate Changes KW - Bivalves KW - Biomarkers KW - Transcriptomic PY - 2018 AN - OPUS4-45474 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schmidt, Stephan A1 - Hoffmann, Holger A1 - Garbe, L.-A. A1 - Harrer, A. A1 - Steiner, M. A1 - Himly, M. A1 - Schneider, Rudolf T1 - New immunoassay for quantification of diclofenac in water samples N2 - Diclofenac (DCF) is a widely used drug against fever, inflammation, pain, and rheumatic diseases. An average of 70 % of the ingested diclofenac is excreted in the urine. Thus, 63 tons per year are introduced into the water cycle in Germany. Due to insufficient removal of diclofenac in wastewater treatment plants, residues of diclofenac can be found in surface water and sometimes in drinking water. In order to establish an immunoassay, an anti-DCF antibody was required. Some antibody developments have been reported, based on an immunogen resulting from direct coupling of diclofenac to proteins via the carboxylic function. Finally, we used a monoclonal antibody, clone F01G21. T2 - Tag der Biotechnologie der TU Berlin CY - Berlin, Germany DA - 13.07.2018 KW - Wasserproben KW - Arzneimittel KW - Antikörper KW - ELISA PY - 2018 AN - OPUS4-45475 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Abbas, Ioana M. A1 - Hoffmann, Holger A1 - Weller, Michael G. T1 - An LC-MS/MS based reference method candidate for the clinical assessment of the promising iron biomarker hepcidin-25 in serum N2 - Hepcidin-25 has attracted much attention ever since its discovery in 2001. It is widely recognized that this peptide hormone plays a major role in the regulation of iron levels in mammals and can reveal important clinical information about several iron-related disorders. However, the development of a reliable assay to quantify hepcidin proved to be problematic and serum hepcidin-25 concentrations determined by various assays differ substantially. Challenges arise in the MS analysis of hepcidin due to the “sticky” character of the peptide and the lack of suitable standards. With the aim to tackle the current difficulties in hepcidin quantification and improve the status of this promising biomarker in the clinical field, we developed a rapid and robust analytical strategy for the quantification of hepcidin-25 in human samples based on HPLC-MS/MS (QqQ) as a reference method candidate to be implemented in routine laboratories. The novelty of the method is the use of amino- and fluoro-silanized autosampler vials to reduce hepcidin interaction to laboratory glassware surfaces. Furthermore, we have investigated two sample preparation strategies and two chromatographic separation conditions where the use of acidic mobile phases was compared with a novel approach involving solvents at high pH containing 0.1% of ammonia. Both methods were carefully validated and applied to clinical samples in an intra-laboratory comparison of two LC-MS/MS methods using the same hepcidin-25 calibrators with very good correlation of the results. T2 - European Mass Spectrometry Conference 2018 CY - Saarbrücken, Germany DA - 11.03.2018 KW - Validation KW - LC-MS/MS peptide quantification KW - Clinical samples PY - 2018 AN - OPUS4-44616 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Lehmann, Paula A1 - Carl, Peter A1 - Schneider, Rudolf T1 - A Rapid Test for Leaching Studies of Biocides from Building Materials N2 - Regardless of its ban in agricultural use, the triazine derivative terbutryn is still used as a biocide against biofouling in building materials, such as façade colors and roof tiles. From there, it is washed off and may contaminate soil and surface waters, where it shows ecotoxicological behavior. For understanding of these leaching processes, analytical methods that can detect terbutryn in traces are necessary. In contrast to separation methods (Gas (GC) or liquid chromatography (LC)) coupled to mass spectrometry (MS), enzyme immunoassays (EIAs) have proven to be adequate tools for environmental monitoring. Compared to GC-or LC-MS, they are cheap, require only limited time and experimental expertise and enable high throughput. For quantification of terbutryn, EIAs have been established, with a limit of detection (LOD) of 50 ng L-1. For leaching experiments however, a lower LOD would be advantageous. For detection of terbutryn we developed a direct competitive ELISA based on a monoclonal antibody: Terbutryn and an enzyme-terbutryn conjugate (“tracer”) compete for the binding sites of the immobilized antibody. The bound tracer converts a colourless substrate into a blue-coloured product, which can be detected via spectrophotometry. For quantification of terbutryn, a sigmoidal calibration curve is used. For establishing of the EIA, a new tracer based on a terbutryn surrogate (“hapten”) was synthesized. After optimization of the experimental conditions, the immunoassay exhibited a more than ten-fold increased sensitivity (LOD: 3 ng L-1), high stability against sample compounds (Ca2+, NaCl) and lower cross-reactivities against structurally related compounds, than reported before. Analysis of spiked samples was possible with high precision (inter-assay CV: < 10 %) and accuracy (recoveries from spiked samples: 89 % ± 10%). We therefore propose it as quick and reliable method for leaching studies of terbutryn out of building materials. T2 - Adlershofer Forschungsforum CY - Berlin, Germany DA - 11.11.2019 KW - ELISA KW - Terbutryne KW - Hapten Immunoassay KW - Triazine herbicide PY - 2019 AN - OPUS4-49595 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -