Comparison of the performance of solid-phase extraction techniques in recovering organophosphorus and organochlorine compounds from water

Solid-phase extraction (SPE) of 11 organochlorine and 24 organophosphorus compounds from aqueous solution was evaluated using different Amberlite (XAD-2 and XAD-7) resin mixtures, reversed-phase C-18 bonded-silica disks, and poly(styrene-divinylbenzene) (SDB) co-polymer disks. Macroreticular resins provided low recoveries and unacceptable reproducibility for some compounds including malathion, methylparathion, ethylparathion, chlorthion and endosulfan compounds. This is probably due to irreversible adsorption or chemical degradation. No relationship was observed between the recoveries and the log K-ow of the compounds. Octadecyl-bonded silica and styrene-divinylbenzene disks provided comparable results for the selected compounds with recovery efficiencies depending on the polarity of the compounds. Good recoveries were achieved for compounds with water solubilities below 300 mg/l or with log K-ow greater than 2. Poor recoveries were obtained for dichlorvos, monocrotophos and dimethoate.