Simplified method for the determination of chlorinated fungicides and insecticides in fruits by gas chromatography.
A fast, reliable method for the determination of more than twenty chlorinated fungicides and insecticides in a variety of fruit samples is presented. The pesticides are extracted from chopped samples with magnetic stirring, after adding 13 ml of acetone-phosphate buffer-brine solution (12:1, v/v) with 5 ml of n-hexane. The continuous module employed allows sequential decolourization of the organic phase, solvent changeover and solid-phase extraction for clean-up and preconcentration purposes. A 1-microl aliquot of the pesticides in ethyl acetate (eluent) is finally injected into the gas chromatograph for separation and identification. The method provides excellent clean-up despite the complexity of the matrices involved. Fruit samples (5-20 g) containing 0.1-1250 ng/g pesticides were analysed with a high precision (4-6%). After contamination of the fruit samples for 12 h, average recoveries >90% at fortification levels of 5-25 ng/g were obtained for most of the pesticides. Positive findings of these pesticides in fruits purchased at local markets were confirmed by GC-MS.
Columé
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A
Analytical Chemistry Division, Faculty of Sciences, University of Córdoba, Spain.
Cárdenas
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S
Gallego
M
M
Valcárcel
M
M
D002849:Chromatography, Gas / Q000379:methods*; D005659:Fungicides, Industrial / Q000032:analysis*; D006843:Hydrocarbons, Chlorinated; D007306:Insecticides / Q000032:analysis*
D005659:Fungicides, Industrial; D006843:Hydrocarbons, Chlorinated; D007306:Insecticides