Determination of benomyl residues in shiitake mushrooms (Lentinula edodes) by liquid chromatography with UV detection.

A method is optimized to determine benomyl (as carbendazim derivative) in shiitake mushrooms. It is based on the extraction of the fungicide with an ethyl acetate-hexane mixture and a further analysis of the extract by high-performance liquid chromatography-UV. Mean recoveries are evaluated and range from 76% to 86% with relative standard deviation between 1.1% and 5.8%. The limit of quantitation (0.5 mg/Kg) is lower than the maximum residue level established by European legislation. The method is successfully applied to the analysis of shiitake mushrooms cultivated on eucalyptus logs treated with Benlate 500 (benomyl as active ingredient) under natural environmental conditions.