Key WordsColumn liquid chromatography Post-col u m n derivatization Dermal pharmacokinetics Furathiocarb, carbofuran, 3-hydroxycarbofuran and 3-ketocarbofuran SummaryA new method to determine simultaneously the amount of furathiocarb and metabohtes: carbofuran, 3-hydroxycarbofuran, and 3-ketocarbofuran in biological tissues such as liver and kidney is described. The method consists of extraction of samples with acetone, filtration, partition, purification of target analytes through a silica gel column and high-performance liquid chromatographic determination with post-column derivatization. Reasonable recoveries for routine analysis were obtained, and the limits of detection (LOD) with fluorescence detection were 0.2, 0.1, 0.1, and 0.2 mg L 1 for furathiocarb, carbofuran, 3-hydroxycarbofuran and 3-ketocarbofuran respectively, with a signal-to-noise ratio of 3. The present method was successfully applied to the dermal pharmacokinetic study of furathiocarb in Sprague-Dawley rats. Carbofuran and 3-hydroxycarbofuran were observed in hver while only carbofuran was detected in kidney.uated in routine residue analysis of crops and meat since they are toxicologically significant [5].Several methods have been reported for the analysis of furathiocarb using gas chromatography (GC) with a nitrogenphosphorous detector (NPD) [3,6], gas chromatography-mass spectrometry (GC-MS) [6,7], and high-performance liquid chromatography (HPLC) with UV [8] or fluorescence [9] for some of its metabolites. To the best of our knowledge, however, there are no related reports on the simultaneous analysis of furathiocarb and its metabolites in the important biological tissues such as liver and kidney, even though the dermal exposure to sprayers or post-application harvesters was reported in greenhouse cultivation of cucumber [10]. In this work, an analytical method using HPLC with post-column derivatization was developed to determine furathiocarb and its three metabolites simultaneously at ppb levels and was successfully