Development of an immunoaffinity-based solid-phase extraction for diazinon Original Research Article

An immunoaffinity column for the selective extraction and concentration of the insecticide diazinon from water samples prior to analysis by high-performance liquid chromatography (HPLC) or enzyme-linked immunosorbent assay (ELISA) has been developed. Polyclonal antibodies raised against diazinon were covalently immobilized on two different support materials. Columns prepared with aminopropyl glass beads were found to be more suitable than columns prepared with hydrazide derivatized azlactone beads due to greater binding capacity, flow rate, and ruggedness. Several different elution strategies were evaluated, including acidic pH and organic solvents. Efficient desorption of bound diazinon was achieved with 50% methanol employing a procedure that involves a brief prewash with 60% methanol prior to loading. The high selectivity of the immunoaffinity columns was demonstrated in experiments with diazinon spiked spring water, river water, and apple juice. The results of this study demonstrate the potential of immunoaffinity columns for the selective extraction and concentration of diazinon prior to analysis.