Immunoassays as high-throughput tools: monitoring spatial and temporal variations of carbamazepine, caffeine and cetirizine in surface and wastewaters.

Carbamazepine (CBZ), caffeine and cetirizine were monitored by enzyme-linked immunosorbent assays (ELISAs) in surface and wastewaters from Berlin, Germany. This fast and cost-efficient method enabled to assess the spatial and temporal variation of these anthropogenic markers in a high-throughput screening. CBZ and cetirizine were detected by the same antibody, which selectively discriminates between both compounds depending on the pH value used in the incubation step. To our best knowledge, this is the first dual-analyte immunoassay working with a single antibody. The frequent sampling with 487 samples being processed allowed for the repeated detection of unusually high concentrations of CBZ and caffeine. ELISA results correlate well with the ones obtained by liquid chromatography tandem mass spectrometry (LC-MS/MS). Caffeine concentrations found in surface waters were elevated by combined sewer overflows after stormwater events. During the hay fever season, the concentrations of the antihistamine drug cetirizine increased in both surface and wastewaters. Caffeine was almost completely removed during wastewater treatment, while CBZ and cetirizine were found to be more persistent. The maximum concentrations of caffeine, CBZ and cetirizine found in influent wastewater by LC-MS/MS were 470, 5.0 and 0.49 μg L(-1), while in effluent wastewater the concentrations were 0.22, 4.5 and 0.51 μg L(-1), respectively. For surface waters, concentrations up to 3.3, 4.5 and 0.72 μg L(-1) were found, respectively.