Analysis of pesticide residues in fruit juices by matrix-solid phase dispersion and gas chromatographic determination

A rapid multiresidue method has been developed for the analysis of pesticides in fruit juices. The compounds studied were two insecticides (endosulfan I, endosulfan II and their metabolite endosulfan sulfate), five fungicides (chlorothalonil, vinclozolin, procymidone, hexaconazole and fenarimol) and two acaricides (dicofol and tetradifon). The method is based on the dispersion of fruit juices on the adsorbent, Florisil, placed in small glass columns, and subsequent extraction of pesticides using a small volume of ethyl acetate. Residue levels were determined by gas chromatography with electron-capture detection. The ECD response for all pesticides was linear in the range of concentrations studied, with correlation coefficients higher than 0.99. Recoveries obtained for pesticides in different fruit juices at various fortification levels were higher than 74%, with relative standard deviations between 1 and 12%. The detection limits ranged from 1 to 5 mug kg(-1). The identity of the pesticides was confirmed by GC-MS.