River analyzer for chlorotriazines with a direct optical immunosensor

An optical immunosensor coupled to a FIA system was evaluated to monitor ch lorotriazine pesticides in river water samples. The assay is based on a sol id-phase fluorescence immunoassay with immobilized analyte derivative and f ree, fluorescence-labeled anti-atrazine or anti-simazine antibodies. The re sponse of the immunoprobe in the presence of cross-reactants structurally s imilar 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 u sed. Monitoring of river water samples in the Ebre area (Tarragona, Spain) during 3 months was carried out. Eighteen measurements were carried out, an d only eight samples could be detected with simazine and atrazine levels ra nging from 0.18 to 1 mu g L-1. The results obtained with the immunosensor w ere validated by chromatographic techniques. The 50-mL water samples were p reconcentrated by on-line solid-phase extraction (SPE) followed by liquid c hromatography-atmospheric pressure chemical ionization-mass spectrometry (L C-APCI-MS). In this way, unequivocal confirmation of the environmental leve ls of the Ebre samples was accomplished. This River ANAlyzer (RIANA) with a n optical immunosensor can be applied for the monitoring of chlorotriazines in river water samples with a total analysis time of 15 min. No false posi tive was detected.