scope:

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 partly decomposed and therefore not quantitatively determined. 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 cleaned up by gel permeation chromatography (GPC) on a polystyrene gel using a cyclohexane/ethyl acetate mixture for elution. In the GPC eluate, carbendazim and thiabendazole are determined by high performance liquid chromatography (HPLC) on a normal phase column and with UV or UV and fluorescence detectors.