Solid-phase microextraction of organophosphorus pesticides from water

Frequent occurrences of pollution in natural drainage by industrial chemicals, especially pesticides, have triggered interest in the development of fast and unambiguous analytical techniques to verify these pollutants in order to facilitate rapid remedial actions. In this work, we report the development of a solid-phase microextraction (SPME) method to analyse two common industrial pesticides in water, i.e. malathion and parathion. SPME analysis facilitates direct analysis of chemical species in aqueous systems and avoids lengthy sample preparation procedures. In this study, we compare five commercially available fibres: 7 microns polydimethylsiloxane, 30 microns polydimethylsiloxane. 85 microns polyacrylate, 65 microns Carbowax-divinylbenzene and 65 microns polydimethylsiloxane-divinylbenzene fibres. Profiles of uptake by the fibres against adsorption times were established. The results obtained indicated that the polarity of the fibres is not the main factor affecting the uptake. The structures of the fibres also affected the permeation of the analytes onto the fibres. The limits of detection were determined to be in the low ppb level with a flame ionization detector. These methods have great potential for use in rapid on-site analytical work which is highly demanded in environmental studies.