TY - GEN A1 - Carl, Peter A1 - Schneider, Rudolf T1 - Determination of pharmacologically active compounds in wastewater by a bead-based flow-cytometric immunoarray N2 - The assessment of water quality demands for multi-target compatible analytical methods. On the one hand, the influence of sewage on natural surface waters must be routinely monitored. On the other hand, estimation of removal efficiencies of pollutants, such as drug residues, is in the focus of industrial and public wastewater treatment. Immunoassays, such as ELISA, are often applied in this area, however, it is only possible to measure a single analyte in one measurement. In contrast, array technology is capable for measuring multiple substances in parallel. Here we present a four-plex bead-based flow cytometric assay for measuring three drugs (carbamazepine, an antiepileptic drug, diclofenac, an antiphlogistic and caffeine, a psychoactive substance) and the bile acid isolithocholic acid, which is proposed to be used as a fecal marker. In this suspension array core-shell particles, consisting of a polystyrene core and a silica shell, are used. They can be easily encoded with a fluorophore which is introduced to the core while the shell is functionalized with amino groups to which the analytes or their derivates are bound via NHS chemistry. They are the competitor binding sites for the antibodies. For the determination of the pollutants, the beads are incubated with a mixture of the analyte-specific antibodies. The molecules on the surface of the beads and the free analyte in solution compete for the binding sites of the antibodies. Bead-bound antibodies can then be visualized via dye-labelled secondary antibodies. For read-out a flow cytometer is used to virtually separate the differently encoded beads. In order to obtain highly selective binding of the antibodies, we investigated different types of surface modifications to overcome unspecific binding, finding that a PEG-based surface is suitable to support our immunoassay format. The resulting multiplexing assay is appropriate to detect the marker substances in the low µg/L range. T2 - Pittcon 2017 CY - Chicago, IL, USA DA - 05.03.2017 KW - Immunoassay KW - Bead-based assay KW - Flow-cytometry KW - Anthropogenic markers PY - 2017 UR - https://opus4.kobv.de/opus4-bam/frontdoor/index/index/docId/39524 AN - OPUS4-39524 AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany