INVESTIGATIONS ON THE APPLICABILITY OF 2 ELISA TYPES FOR THE DETERMINATION OF CHLORPYRIFOS IN SOIL SAMPLES COMPARED WITH A GAS-CHROMATOGRAPHIC METHOD

Two commercially available ELISA kits for water analysis, a microtiter plate-ELISA based on polyclonal antibodies (p-ELISA) and a magnetic p article tube-ELISA based on monoclonal antibodies (t-ELISA), were used to determine chlorpyrifos residues in soils. Comparison with a gas ch romatographic method frequently applied was carried out by fortificati on experiments and by analyses of real soil samples. At concentration levels of 1.0, 0.1, 0.05 and 0.01 mg/kg, chlorpyrifos was reliably det ermined by the GC method. Application of the p-ELISA did not permit a reliable quantitation, while the t-ELISA was applicable in a concentra tion range of 0.05-1.0 mg chlorpyrifos/kg dry soil.