Determination of thiabendazole residues in white and sweet potatoes by liquid chromatography with fluorescence detection.

A liquid chromatographic (LC) method was developed for determination of thiabendazole (TBZ) residues in or on whole, unwashed white potatoes (Solanum tuberosum) and sweet potatoes (Ipomoea batatas). TBZ is extracted from the potato homogenate with ethyl acetate and the extract purified and concentrated on a cation-exchange, solid-phase extraction column. The extract is analyzed for TBZ residues by column LC with a cation-exchange column and fluorescence detection. Recoveries of TBZ from whole white potatoes fortified with TBZ at 0.05-20 ppm and from whole sweet potatoes fortified with TBZ at 0.005-0.1 ppm averaged 100 and 94%, respectively. The method is also applicable for quantitation of TBZ residues in white potato waste (dried peel) used as an animal feed additive. The present method for monitoring TBZ residues in white and sweet potatoes and white potato waste (dried peel) is simple, rapid, and sensitive.