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This document specifies a high performance liquid chromatographic method for the determination of the benzimidazole fungicides carbendazim and thiabendazole in fruits, vegetables and processed products. When benomyl is present, it is completely degraded to carbendazim and is also determined as carbendazim. Thiophanate-methyl is not determined with the method. The method has been validated for carbendazim and thiabendazole in an interlaboratory test with homogenates of apples, French beans, mushrooms, lemons and fruit based infant food. The sample is homogenized with ethyl acetate, sodium hydroxide solution and anhydrous sodium sulfate and the homogenate is filtered. An aliquot portion of the ethyl acetate extract is partitioned with hydrochloric acid solution; the aqueous phase is made alkaline and partitioned with ethyl acetate. The organic layer is evaporated and the residue is dissolved in the HPLC mobile phase. Carbendazim and thiabendazole are determined by reversed-phase high performance liquid chromatography (HPLC) with UV or UV and fluorescence detectors.