Micellar extraction of organophosphorus pesticides and their determination by liquid chromatography

Methodology to extract and determine eight organophosphorus pesticides (Chlorpyrifos, Diazinon, Dimethoate, Ethoprophos, Malathion, Methidathion, Parathion methyl and Paration ethyl), that are in current use in agriculture and animal husbandry, was optimised. The surfactants used as extractants, polyoxyethylene 10 lauryl ether (POLE) and oligoethylene glycol monoalkyl ether (Genapol X-080), belong to the non-ionic surfactants family, which allow the extraction and preconcentration of the analytes under study in a single step. This procedure, known as cloud-point extraction, offers a series of advantages over the traditional methodologies applied to the extraction of organic compounds such as pesticides. The parameters and variables that affect the extraction of these substances using both surfactants were established followed by liquid chromatographic determination. The optimised method, once validated using the standard Pesticide Mix 1 (EPA Method 914), was successfully applied to spiked water samples from Gran Canaria Island.