TY - JOUR A1 - Silva, C.P. A1 - Lima, D.L.D. A1 - Schneider, Rudolf A1 - Otero, M. A1 - Esteves, V.I. T1 - Development of ELISA methodologies for the direct determination of 17beta-estradiol and 17alpha-ethinylestraydiol in complex aqueous matrices N2 - This study comprises the development of enzyme-linked immunosorbent assays (ELISAs) for the quantification of 17β-estradiol (E2) and 17α-ethinylestradiol (EE2) in complex aqueous matrices without any sample clean-up procedures. Salinity and dissolved organic matter were selected as potential interfering agents in the analysis of E2 and EE2. The optimization was performed in order to (i) overcome matrix effects, and to (ii) increase sensitivity. The addition of a sample buffer containing bovine serum albumin (BSA) prior to the sample was found to decrease the influence of matrix effects. Moreover, adjustments of this buffer's pH together with the optimization of tracer (T) dilution and incubation time were undertaken in order to lower the quantification range. The optimized methods allowed the quantification of E2 and EE2 in the ranges 0.03–200 µg L-1 and 0.02–10 µg L-1, respectively. The assays were applied to real aqueous samples. It was possible to do a first approach to the levels of E2 in Portuguese surface and waste waters; however, it was not feasible to detect EE2 in the samples tested. KW - Enzyme-linked immunosorbent assay KW - Endocrine disrupting compounds KW - 17beta-Estradiol KW - 17alpha-Ethinylestradiol KW - Surface water KW - Wastewater PY - 2013 U6 - https://doi.org/10.1016/j.jenvman.2013.03.041 SN - 0301-4797 SN - 1095-8630 VL - 124 SP - 121 EP - 127 PB - Elsevier Ltd. CY - Amsterdam AN - OPUS4-28516 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Hoffmann, Holger A1 - Baldofski, Stefanie A1 - Hoffmann, Kristin A1 - Flemig, Sabine A1 - Silva, C. P. A1 - Esteves, V. I. A1 - Emmerling, Franziska A1 - Panne, Ulrich A1 - Schneider, Rudolf T1 - Structural considerations on the selectivity of an immunoassay for sulfamethoxazole N2 - Sulfamethoxazol (SMX),a sulfonamide, is a widely used bacteriostatic antibiotic and therefore a promising marker for the entry of anthropogenic Pollution in the environment. SMX is frequently found in wastewater and surface water. This study presents the production of high affinity and selective polyclonal antibodies for SMX and the development and Evaluation of a direct competitive enzyme-linked immunosorbent assay(ELISA)for the quantification of SMX in environmental watersamples. The crystal structures of the cross-reacting compounds sulfamethizole, N4-acetyl-SMX andsuccinimidyl-SMX were determined by x-ray diffraction aiming to explain their high cross-reactivity. These crystal structures are described for the first time. The quantification range of the ELISA is 0.82–63 µg/L. To verify our results, the SMX concentration in 20 environmental samples,including wastewater and surfacewater,was determined by ELISA and tandem mass spectrometry(MS/MS).A good Agreement of the measured SMX concentrations was found with average recoveries of 97–113%for the results of ELISA compared to LC-MS/MS. KW - X-Ray diffraction KW - Sulfamethoxazole KW - ELISA KW - LC-MS/MS PY - 2016 U6 - https://doi.org/10.1016/j.talanta.2016.05.049 SN - 0039-9140 SN - 1873-3573 IS - 158 SP - 198 EP - 207 PB - Elsevier B.V. CY - Amsterdam, Netherlands AN - OPUS4-36676 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Silva, C.P. A1 - Lima, D.L.D. A1 - Schneider, Rudolf A1 - Otero, M. A1 - Esteves, V.I. T1 - Evaluation of the anthropogenic input of caffeine in surface waters of the north and center of Portugal by ELISA N2 - This study comprises the development of an enzyme-linked immunosorbent assay (ELISA) for the quantification of caffeine in complex aqueous matrices without any sample clean-up procedure. Salinity and dissolved organic matter were selected as potential interfering agents. The addition of a sample buffer containing bovine serum albumin (BSA) prior to the sample was found to decrease the influence of those interfering agents. The working range of the developed method was 0.1–100 µg L- 1. Quantification of caffeine was possible in 43 out of 51 real aqueous samples, at values between < LOD and 15 µg L- 1. Results correlate well with those obtained by LC–MS/MS. To the best of our knowledge this is the first study dealing with the quantification of caffeine in Portugal's surface waters. KW - Caffeine KW - Surface water KW - ELISA KW - Anthropogenic markers KW - Koffein KW - Eintrag KW - Oberflächenwasser KW - Gewässer KW - Abwasser KW - Antikörper KW - Immunoassay PY - 2014 U6 - https://doi.org/10.1016/j.scitotenv.2014.01.120 SN - 0048-9697 VL - 479-480 SP - 227 EP - 232 PB - Elsevier CY - Amsterdam AN - OPUS4-30450 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Lima, D.L.D. A1 - Silva, C.P. A1 - Schneider, Rudolf A1 - Otero, M. A1 - Esteves, V.I. T1 - Application of dispersive liquid-liquid microextraction for estrogens' quantification by enzyme-linked immunosorbent assay N2 - Estrogens, such as 17β-estradiol (E2) and 17α-ethinylestradiol (EE2), are the major responsible for endocrine-disrupting effects observed in aquatic environments due to their high estrogenic potency, even at concentrations ranging from pg L-1 to ng L-1. Thus, it is essential to develop analytical methodologies suitable for monitoring their presence in water samples. Dispersive liquid–liquid microextraction (DLLME) was used as a pre-concentration step prior to the quantification of E2 and EE2 by enzyme-linked immunosorbent assay (ELISA). First, an evaluation of the effect of DDLME on the E2 and EE2 ELISA calibration curves was performed. Since the extraction procedure itself had an influence on the ELISA optical density (OD), it became necessary to subject, not only the samples, but also all the standards to the DLLME process. Working ranges were determined, being between 1.2 and 8000 ng L-1, for E2, and between 0.22 and 1500 ng L-1, for EE2. The influence of organic matter, both in the extraction and quantification, was evaluated and it was observed that its presence in the solution did not affect considerably the calibration curve. Recovery rates were also determined, ranging from 77% to 106% for ultrapure water and from 104% to 115% for waste water samples, the most complex ones in what concerns matrix effects. Results obtained when applying the proposed method to real water samples can be considered quite satisfying. Moreover, the obtained working ranges encompass values generally reported in literature, confirming the practical use of the method for environmental samples. KW - DLLME KW - ELISA KW - Water samples KW - Environment KW - 17beta-estradiol KW - 17alpha-ethinylestradiol PY - 2014 U6 - https://doi.org/10.1016/j.talanta.2014.02.069 SN - 0039-9140 VL - 125 SP - 102 EP - 106 PB - Elsevier CY - Amsterdam AN - OPUS4-30614 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Lima, D.L.D. A1 - Silva, C.P. A1 - Schneider, Rudolf A1 - Esteves, V.I. T1 - Development of an ELISA procedure to study sorption of atrazine onto a sewage sludge-amended luvisol soil N2 - Pesticides may contaminate ground and surface waters and one of the major factors governing this property is soil sorption. Sorption can be assessed by batch equilibrium technique which produces lots of extracts with high dissolved organic carbon concentration in which the pesticide concentration has to be determined. We developed an ELISA procedure to analyse atrazine based on polyclonal antibodies (C193) for which tracer structure and dilutions of immunochemical reagents were adapted to fit the purpose. After a 1000-fold dilution (or after an SPE clean-up procedure) extracts of a sewage-sludge amended luvisol (used as an example application of the methodology developed) could be reliably analysed. The Freundlich model is able to describe adsorption for this system (r² = 0.977) delivering a distribution coefficient KF of 1.6 ± 0.2 (mg kg-1) (mg L-1)-N and an isotherm nonlinearity factor N of 0.70 ± 0.09. KW - ELISA KW - Atrazine KW - Sorption PY - 2011 U6 - https://doi.org/10.1016/j.talanta.2011.06.024 SN - 0039-9140 VL - 85 IS - 3 SP - 1494 EP - 1499 PB - Elsevier B.V. CY - Amsterdam AN - OPUS4-24305 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Hoffmann, Holger A1 - Baldofski, Stefanie A1 - Hoffmann, Kristin A1 - Flemig, Sabine A1 - Silva, C. P. A1 - Esteves, V. I. A1 - Emmerling, Franziska A1 - Panne, Ulrich A1 - Schneider, Rudolf T1 - Structural considerations on the selectivity of an immunoassay for sulfamethoxazole N2 - Sulfamethoxazol (SMX),a sulfonamide, is a widely used bacteriostatic antibiotic and therefore a promising marker for the entry of anthropogenic Pollution in the environment. SMX is frequently found in wastewater and surface water. This study presents the production of high affinity and selective polyclonal antibodies for SMX and the development and Evaluation of a direct competitive enzyme-linked immunosorbent assay(ELISA)for the quantification of SMX in environmental watersamples. The crystal structures of the cross-reacting compounds sulfamethizole, N4-acetyl-SMX andsuccinimidyl-SMX were determined by x-ray diffraction aiming to explain their high cross-reactivity. These crystal structures are described for the first time. The quantification range of the ELISA is 0.82–63 µg/L. To verify our results, the SMX concentration in 20 environmental samples,including wastewater and surfacewater,was determined by ELISA and tandem mass spectrometry(MS/MS).A good Agreement of the measured SMX concentrations was found with average recoveries of 97–113%for the results of ELISA compared to LC-MS/MS. KW - X-Ray diffraction KW - ELISA KW - LC-MS/MS KW - Sulfamethoxazole PY - 2016 U6 - https://doi.org/10.1016/j.talanta.2016.05.049 SN - 0039-9140 SN - 1873-3573 IS - 158 SP - 198 EP - 207 PB - Elsevier B.V. CY - Amsterdam, Netherlands AN - OPUS4-38530 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Silva, C. P. A1 - Carvalho, T. A1 - Schneider, Rudolf A1 - Esteves, V. I. A1 - Lima, D. L. D. T1 - ELISA as an effective tool to determine spatial and seasonal occurrence of emerging contaminants in the aquatic environment N2 - During the last two decades, studies related to the occurrence and fate of emerging contaminants in the aquatic environment have received great attention from the international scientific community. The monitoring of the presence of these compounds is particularly important since they are known to induce adverse effects in aquatic environments, even at extremely low concentrations. This work aimed to apply a simple and effective methodology, such as enzyme-linked immunosorbent assay (ELISA), in the monitoring of 17a-ethinylestradiol (EE2) and 17b-estradiol (E2) (a synthetic and a natural hormone, respectively), carbamazepine (CBZ, an antiepileptic), cetirizine (CET, an antihistamine) and caffeine (CAF, a stimulant) in water matrices with differing salinity and organic matter contents. ELISA was proven to be a valid and practical tool, especially for screening purposes in contrast to traditional chromatographic techniques which are prohibitively expensive for an application on a broader base. The main originality of this work was to establish seasonal and spatial effects on the occurrence of the referred contaminants by using the effectiveness of ELISA to screen those compounds in samples with different characteristics. This work reports both the seasonal and spatial quantification of the referred contaminants in the aquatic environment of the central region of Portugal, with concentrations ranging as follows: 5–87 ng L-1, for E2, 2–17 ng L-1, for EE2, 10–1290 ng L-1, for CBZ, 10–190 ng L-1, for CET, and 62–6400 ng L-1, for CAF. KW - Estrogen KW - Estradiol KW - Ethinylestradiol KW - Carbamazepine KW - Portugal KW - Wasser PY - 2020 U6 - https://doi.org/10.1039/D0AY00426J SN - 1759-9679 VL - 12 IS - 19 SP - 2517 EP - 2526 PB - Royal Society of Chemistry RSC CY - London AN - OPUS4-51340 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -