An improved method for extraction of organochlorine and organophosphate insecticides from lake waters

Abstract

The sensitivity of a benzene extraction method, described previously, for the extraction of organochlorine and organophosphate insecticides from lake waters has been increased from 20 to 200 times with the little loss in accuracy or reproducibility. The added sensitivity was accomplished by increasing the water-to-extractant ratio, and including a concentration step. Average recoveries of γ-BHC, aldrin, heptachlor epoxide, dieldrin, endrin, pp′-TDE, pp′-DDT, pp′-methoxychlor, phorate, parathion-methyl, diazinon, parathion and malathion ranged from 94 to 99 per cent. at concentrations of 0·0620 to 1·16 µg l^–1, depending on gas-liquid chromatographic detector response. The average recovery of heptachlor was 89 per cent., presumably arising from loss of heptachlor from the system either by degradation or volatilisation.