TY - JOUR A1 - Grandke, Julia A1 - Oberleitner, Lidia A1 - Resch-Genger, Ute A1 - Garbe, L.-A. A1 - Schneider, Rudolf T1 - Quality assurance in immunoassay performance - comparison of different enzyme immunoassays for the determination of caffeine in consumer products N2 - Enzyme immunoassays with optical detection are amongst the most widely used bioanalytical tools. We defined seven parameters for the quality assessment of immunoassays that were addressed in a systematic study of direct and indirect immunoassays, using the enzymes horseradish peroxidase (HRP) and alkaline phosphatase (AP), the chromogenic substrates 3,3',5,5'-tetramethylbenzidine (TMB) and para-nitrophenyl phosphate, and the fluorescent substrates 3-(4-hydroxyphenyl)propionic acid and 4-methylumbelliferyl phosphate. The same monoclonal antibody against caffeine was used throughout the study. The four quality parameters regarding the standard curve were the test midpoint (sensitivity), the measurement range, the relative dynamic range of the signal, and the goodness of fit of the adjusted four-parameter logistic function. All HRP immunoassays showed a higher sensitivity compared to the AP assays. On the basis of all four criteria, it was established that the direct assay format is superior to the indirect format, the immunoassay using HRP TMB fulfilling all requirements best. In a second step, caffeine concentrations in 24 beverage and cosmetics samples were determined and three more quality parameters were assessed with this application. The direct HRP TMB assay showed one of the best intra- and inter-plate precisions and the best accuracy, defined by the correlation of results with those from the chosen reference method liquid chromatography tandem mass spectrometry (LC-MS/MS). Considering all criteria, HRP TMB seems to be the enzyme substrate system of choice preferably used in the direct assay format. KW - Enzyme immunoassay KW - Caffeine KW - Enzyme substrate KW - Competitive assay KW - Assay format KW - Direct KW - Indirect PY - 2013 U6 - https://doi.org/10.1007/s00216-012-6596-0 SN - 1618-2642 SN - 1618-2650 VL - 405 IS - 5 SP - 1601 EP - 1611 PB - Springer CY - Berlin AN - OPUS4-27639 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Oberleitner, Lidia A1 - Grandke, Julia A1 - Schneider, Rudolf A1 - Garbe, L.-A. T1 - Application and evaluation of carbamazepine immunoassays T2 - ANAKON 2013 CY - Essen, Germany DA - 2013-03-04 PY - 2013 AN - OPUS4-27814 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Oberleitner, Lidia A1 - Grandke, Julia A1 - Schneider, Rudolf A1 - Mallwitz, F. A1 - Garbe, L.-A. T1 - Fluorescense Polarization Immunoassays for Caffeine T2 - Euroanalysis 2013 CY - Warsaw, Poland DA - 2013-08-25 PY - 2013 AN - OPUS4-28995 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Oberleitner, Lidia A1 - Lehmann, Andreas A1 - Schneider, Rudolf A1 - Garbe, L.-A. A1 - Eremin, Sergei A. T1 - Fluorescense Polarization Immunoassays for Carbamazepine T2 - 24th Symposium on Pharmaceutical and Biomedical Analysis CY - Bologna, Italy DA - 2013-06-30 PY - 2013 AN - OPUS4-28946 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Grandke, Julia A1 - Oberleitner, Lidia A1 - Resch-Genger, Ute A1 - Garbe, L.-A. A1 - Schneider, Rudolf T1 - Quality assurance in immunoassay performance - carbamazepine immunoassay format evaluation and application on surface and waste water N2 - Carbamazepine (CBZ) is one of the most frequently detected pharmaceuticals in water samples. For the determination of this anthropogenic marker, various immunoassay formats were tested and evaluated in order to identify the most suitable one. For these direct competitive assays, the analyte was labelled with the enzyme horseradish peroxidase (HRP) or alkaline phosphatase (AP), and seven substrates with specific detection properties were used. The quality criteria for the standard curves were fulfilled by all HRP assays and the chemiluminescence AP format. Furthermore, intra- and inter-plate coefficients of variation as a measure of the achievable precision were determined for the samples. The application of the AP assays to surface water was unfeasible due to CBZ concentrations below the quantifiable concentration range. Surface as well as waste water samples could be analyzed with the HRP assays. Here, the HRP assay employing the chromogenic substrate 3,3',5,5'-tetramethylbenzidine yielded the best results. PY - 2013 U6 - https://doi.org/10.1039/c3ay40702k SN - 1759-9660 SN - 1759-9679 VL - 5 IS - 15 SP - 3754 EP - 3760 PB - RSC Publ. CY - Cambridge AN - OPUS4-28860 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Oberleitner, Lidia A1 - Grandke, Julia A1 - Schneider, Rudolf A1 - Mallwitz, F. A1 - Garbe, L.-A. A1 - Leif-Alexander, T1 - Comparison of Heterogeneous and homogeneous Immunoassays T2 - Trends in Diagnostics CY - Tübingen, Germany DA - 2013-10-07 PY - 2013 AN - OPUS4-29238 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Oberleitner, Lidia A1 - Mallwitz, F. A1 - Garbe, L.-A. A1 - Schneider, Rudolf T1 - New monoclonal anti-carbamazepine antibody for application in fluorescence polarization immunoassays T2 - Analytica Conference 2014 CY - Munich, Germany DA - 2014-04-01 PY - 2014 AN - OPUS4-30516 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Oberleitner, Lidia A1 - Grandke, Julia A1 - Mallwitz, F. A1 - Resch-Genger, Ute A1 - Garbe, L.-A. A1 - Schneider, Rudolf T1 - Fluorescence polarization immunoassays for the quantification of caffeine in beverages N2 - Homogeneous fluorescence polarization immunoassays (FPIAs) were developed and compared for the determination of caffeine in beverages and cosmetics. FPIAs were performed in cuvettes in a spectrometer for kinetic FP measurements as well as in microtiter plates (MTPs) on a multimode reader. Both FPIAs showed measurement ranges in the µg/L range and were performed within 2 and 20 min, respectively. For the application on real samples, high coefficients of variations (CVs) were observed for the performance in MTPs; the CVs for FPIAs in cuvettes were below 4%. The correlations between this method and reference methods were satisfying. The sensitivity was sufficient for all tested samples including decaffeinated coffee without preconcentration steps. The FPIA in cuvettes allows a fast, precise, and automated quantitative analysis of caffeine in consumer products, whereas FPIAs in MTPs are suitable for semiquantitative high-throughput screenings. Moreover, specific quality criteria for heterogeneous assays were applied to homogeneous immunoassays. KW - caffeine KW - Decaffeinated coffee KW - Fluorescence polarization immunoassay KW - Homogeneous immunoassay KW - Quality assurance criteria PY - 2014 U6 - https://doi.org/10.1021/jf4053226 SN - 0021-8561 SN - 1520-5118 VL - 62 IS - 11 SP - 2337 EP - 2343 PB - American Chemical Society CY - Columbus, Ohio AN - OPUS4-30613 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Oberleitner, Lidia A1 - Schneider, Rudolf A1 - Garbe, L.-A. T1 - Fluorescence polarization immunoassay - Fast Screening method for antibody characterization T2 - Tag der Biotechnologie CY - Berlin, Germany DA - 2015-07-16 PY - 2015 AN - OPUS4-34514 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Oberleitner, Lidia A1 - Grandke, J. A1 - Schneider, Rudolf T1 - Fluorescence polarization immunoassay - the fast alternative to ELISA T2 - Schnell, schneller, Optik - wie optische Technologien die Lebensmittel- und Umweltanalytik optimieren CY - Berlin DA - 2014-11-27 PY - 2014 AN - OPUS4-32143 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -