TY - JOUR A1 - Calisto, V. A1 - Bahlmann, Arnold A1 - Schneider, Rudolf A1 - Esteves, V.I. T1 - Application of an ELISA to the quantification of carbamazepine in ground, surface and wastewaters and validation with LC-MS/MS N2 - Carbamazepine is a psychiatric pharmaceutical widely detected in aquatic environments. Due to its generalized occurrence and environmental persistence it might be considered as an anthropogenic pollution indicator. In this research, a previously developed enzyme-linked immunosorbent assay (ELISA), based on a commercial monoclonal antibody, was applied to the quantification of carbamazepine in ground, surface and wastewaters and results were validated by liquid chromatography–tandem mass spectrometry (LC–MS/MS). The performance of the applied ELISA methodology was tested in the presence of high concentrations of sodium chloride and dissolved organic matter. The method was not significantly affected by matrix effects, being adequate for the quantification of carbamazepine in environmental samples, even without sample pre-treatment. This method allows the quantification of carbamazepine in the range of 0.03–10 µg L-1, with a relative error lower than 30%. Due to a pH dependent cross-reactivity with cetirizine, an antihistaminic drug, the assay also enabled the quantification of cetirizine in the samples. The application of the developed method to the quantification of carbamazepine was performed by using environmental samples with very different matrices, collected in the geographical area of Ria de Aveiro, an estuarine system located in the North of Portugal. Carbamazepine was detected in all analyzed wastewater samples and in one surface water with concentrations between 0.1 and 0.7 µg L-1. Validation with LC–MS/MS revealed that results obtained by ELISA are 2–28% overestimated, which was considered highly satisfactory due to the absence of sample pre-treatments. KW - Immunoassay KW - Pharmaceuticals KW - Environment KW - Wastewater treatment plants KW - Matrix effects KW - Cetirizine PY - 2011 U6 - https://doi.org/10.1016/j.chemosphere.2011.04.072 SN - 0045-6535 SN - 0366-7111 VL - 84 IS - 11 SP - 1708 EP - 1715 PB - Elsevier Science CY - Kidlington, Oxford AN - OPUS4-24306 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 -