River analyzer for chlorotriazines with a direct optical immunosensor

An optical immunosensor coupled to a FIA system was evaluated to monitor chlorotriazine pesticides in river water samples. The assay is based on a solid-phase fluorescence immunoassay with immobilized analyte derivative and free, fluorescence-labeled anti-atrazine or anti-simazine antibodies. The response of the immunoprobe in the presence of cross-reactants structurally similar to atrazine (simazine, deisopropylatrazine, and deethylatrazine) was studied. Limits of detection for atrazine and simazine varied between 0.06 and 0.2 mu g L-1, depending if Milli-Q water or river water samples were used. Monitoring of river water samples in the Ebre area (Tarragona, Spain) during 3 months was carried out. Eighteen measurements were carried out, and only eight samples could be detected with simazine and atrazine levels ranging from 0.18 to 1 mu g L-1. The results obtained with the immunosensor were validated by chromatographic techniques. The 50-mL water samples were preconcentrated by on-line solid-phase extraction (SPE) followed by liquid chromatography-atmospheric pressure chemical ionization-mass spectrometry (LC-APCI-MS). In this way, unequivocal confirmation of the environmental levels of the Ebre samples was accomplished. This River ANAlyzer (RIANA) with an optical immunosensor can be applied for the monitoring of chlorotriazines in river water samples with a total analysis time of 15 min. No false positive was detected.