Simultaneous determination of several pesticides with chemiluminescent immunoassay on a multi-spot membrane strip

Chemiluminescent immunoassay with two types of a multispot membrane strip has been developed for the simultaneous determination of several pesticides in water samples. Three types of antibodies with different cross-reactivity towards s-triazines were immobilized in three separate spots of the first strip (called a 'triazine membrane strip') by means of a photoimmobilization technique. The second strip (called a 'pesticide membrane strip') contained two pesticide-specific spots with immobilized antibodies, one specific to 2,4-dichlorophenoxyacetic acid and another with a high extent of cross-reactivity toward different s-triazines. Each membrane strip contained two additional spots. One was employed as a positive control or cut-off spot, and the other one was used to check the background luminescence. The immunoassay with a multispot membrane strip allowed us to estimate semi-quantitatively the concentration for a particular analyte by a comparison of the recorded light intensifies of the analyte spot and the cut-off spot. The application of the triazine membrane strip provides a differentiation between atrazine, simazine and terbuthylazine in mixtures, and the pesticide membrane strip allows the performance of group-specific assays.