Title: Evaluation of organophosphorus pesticide residues in citrus fruits from the Valencian community (Spain) Torres CM, Pico Y, Marin R, Manes J Ref: Journal of AOAC International, 80:1122, 1997 : PubMed
Approximately 200 citrus samples from markets of the Valencian Community (Spain) were analyzed to establish their residue levels in 12 organophosphorus pesticide residues during the 1994-1995 campaign. The organophosphorus pesticides carbophenothion, chlorpyriphos, chlorfenvinphos, diazinon, ethion, fenitrothion, malathion, methidation, methylparathion, phosmet, quinalphos, and tetradifon were simultaneously extracted by matrix solid-phase dispersion and determined by gas chromatography-mass spectrometry using selected ion monitoring mode. A total of 32.25% contained pesticide residues and 6.9% exceeded the European Union Maximum Residue Levels (MRLs). The pesticides found in the samples with residues above MRLs were carbophenothion, ethion, methidathion, and methyl parathion. Lower level residues of these and the other pesticides studied (except diazinon) were frequently found. The estimated daily intake of the 12 organophosphorus pesticide residues during the studied period was 4.87 x 10(-4) mg/kg body weight/day. This value is lower than the provisional tolerances dairy intakes proposed by the Food and Agriculture Organization and the World Health Organization.
Title: Matrix solid-phase dispersion extraction procedure for multiresidue pesticide analysis in oranges Torres CM, Pico Y, Redondo MJ, Manes J Ref: Journal of Chromatography A, 719:95, 1996 : PubMed
A multiresidue extraction method based on matrix solid-phase dispersion (MSPD) is optimized for the extraction and gas chromatographic screening of eighteen insecticides (aldrin, carbophenothion, captafol, chlorpyriphos, chlorfenvinphos, diazinon, dicofol, alpha-endosulfan, beta-endosulfan, ethion, fenitrothion, folpet, methidathion, malathion, methyl-azinphos, methyl-parathion, phosmet, and tetradifon) from oranges. After optimization of different parameters, such as type of solid phase used and the amount of solid phase or eluent, recoveries ranged from 67 to 102% with relative standard deviations ranging from 2 to 10%. The limits of detection, calculated as 3 times the baseline noise ranged from 2 to 171 micrograms/kg. These limits of detection were about 10 times lower than the maximum residue levels established by the European Community. Compared with classical methods, the described procedure is simple, less labour intensive and does not require preparation and maintenance of equipment. Troublesome emulsions, such as those frequently observed in liquid-liquid partitioning did not occur.
