Determination of organophosphorus pesticides in honeybees after solid-phase microextraction

A method based on solid-phase microextraction (SPME) followed by gas chroma tography with nitrogen-phosphorus detection was developed for the purpose o f determining 18 organophosphorus pesticide residues in honeybee samples (A pis mellifera). The extraction capacities of polyacrylate and poly(dimethyl siloxane) fibers were compared. The main factors affecting the SPME process , such as the absorption time profile, salt, and temperature, were optimize d. The method involved honeybee sample homogenization, elution with an acet one:water solution (1:1) and dilution in water prior to fiber extraction. M oreover, the matrix effect on the extraction was evaluated. In samples spik ed at the 0.2 mg kg(-1) level, the coefficient variation was between 1 and 13% and the detection limits were below 10 mug kg(-1). The SPME procedure w as found to be quicker and more cost-effective than the solvent extraction method commonly used. The method was applied successfully to environmental screening. Parathion methyl was detected and confirmed in the real samples analyzed. (C) 2001 Elsevier Science B.V. All rights reserved.