Conversion of a conventional packed-column gas chromatograph to accommodate megabore columns. II. Determination of organophosphorus insecticides in environmental water.

Several methods involving solvent extraction or solid extraction (Amberlite XAD resins) were studied for the multi-residue recovery of fourteen organophosphorus compounds in water. It was found that extraction with ethyl acetate in a salted medium provided the most consistent data, both in terms of number of compounds recovered and percentage recovery. Amberlite XAD resins gave consistently high recoveries, and this was attributed to a matrix effect upon the particular nitrogen-phosphorus detector. The evaluation was made using a megabore column installed in a conventional packed-column chromatograph, and the results show that such a system is amenable to the multi-residue analysis of organophosphorus pesticides at very low costs.