Automated extraction and preconcentration of multiresidue of pesticides on a micro-solid-phase extraction system based on polypyrrole as sorbent and off-line monitoring by gas chromatography-flame ionization detection.

A simple and efficient automated method for extraction and preconcentration of some organophosphorus and organochlorine pesticides from drinking and agriculture waters has been developed. In this work, a pyrrole-based polymer was synthesized and applied as an efficient sorbent for micro-solid-phase extraction (mu-SPE). Polypyrrole (PPY) was synthesized by chemical oxidation of the monomer in nonaqueous solution. The mu-SPE of selected pesticides, from aqueous samples was performed using 20mg of PPY. After extraction, analytes were desorbed in ethyl acetate and analyzed using gas chromatography-flame ionization detection. The acid-base and other physico-chemical interactions with the analytes facilitated the adsorption of analytes, with good selectivity and reproducibility. Under the optimized extraction conditions, the method showed good linearity in the range of 0.001-0.3 microg ml(-1) of water sample (phosphate buffer 1.0 x 10(-3) M, pH 8.5), RSD=1.5-4.2% (n=4), and limits of detection 200-600 pg ml(-1). Each mu-SPE cartridge could be used for up to 20 extractions.