title: Determination of carbendazim, thiabendazole, and o-phenylphenol residues in lemons by HPLC following sample clean-up by ion-pairing.
abstract: An efficient analytical method is presented involving effective sample clean-up with solid-phase extraction and HPLC-UV analysis for the simultaneous determination of carbendazim, thiabendazole, and o-phenylphenol residues in lemons. Sample preparation involves extraction with acetonitrile acidified with trifluoroacetic acid and an ethyl acetate/petroleum ether mixture. Purification of the crude extract was carried out with liquid-liquid partitioning after addition of an aqueous ammonia solution. Final clean-up was performed on polymeric reversed-phase cartridges pretreated with sodium dodecyl sulfate. Chromatographic analysis was performed on a reversed-phase HPLC column isocratically eluted with an acetonitrile/water/ammonia mixture and UV detection at 254 nm. The chromatographic method is repeatable, reproducible, and sensitive. Fungicide recoveries from lemon samples fortified at levels of 5 and 1 mg kg(-1) were 81-85% for carbendazim, 96-98% for thiabendazole, and 81-106% for o-phenylphenol with coefficients of variation of 2.5-7.4%. Detection limits for carbendazim, thiabendazole, and o-phenylphenol in lemons were 0.21, 0.27, and 0.51 mg kg(-1), respectively.
authors.affiliation: Department of Chemistry, Section of Organic Chemistry, Biochemistry and Natural Products, University of Patras, 26500 Patras, Greece.
authors.forename: Konstantinos P
authors.initials: KP
authors.lastname: Prousalis
authors.forename: Dimitris A
authors.initials: DA
authors.lastname: Polygenis
authors.forename: Alexandra
authors.initials: A
authors.lastname: Syrokou
authors.forename: Fotini N
authors.initials: FN
authors.lastname: Lamari
authors.forename: Theodore
authors.initials: T
authors.lastname: Tsegenidis