Aharonson, N., Beltsville Agricultural Research Center, Agricultural Research Service, U.S. Department of Agriculture, Beltsville, MD 20705, United States, Agricultural Research Organization, Volcani Center, Bet Dagan 50250, Israel
Lehotay, S.J., Beltsville Agricultural Research Center, Agricultural Research Service, U.S. Department of Agriculture, Beltsville, MD 20705, United States
Ibrahim, M.A., Beltsville Agricultural Research Center, Agricultural Research Service, U.S. Department of Agriculture, Beltsville, MD 20705, United States

An analytical method employing supercritical fluid extraction (SFE) of the benzimidazole fungicides thiabendazole, benomyl/carbendazim, and thiophanate-methyl was developed and tested with potato, banana, and apple matrices. Ion-pairing HPLC coupled with UV absorbance or fluorescence detection was used for analysis. Sample preparation involved shredding a 100 g sample, mixing a 3 g subsample with 2 g of Hydromatrix, and packing a 10 mL vessel. Optimal SFE conditions were determined by varying the amount, density, and flow rate of CO2, extraction temperature, type and amount of solvent modifier, and trapping/elution conditions of the extracted pesticides. Optimal conditions for extraction were obtained at 400 atm, 60°C, 90 g of CO2, 3% methanol modifier, and 2 mL/min flow rate. The extracts were collected on a 1 mL C18 trap at 25°C and eluted with 10 mL of methanol. Potato, apple, and banana extracts were analyzed by HPLC without additional cleanup. Recoveries were 90 ± 12% for the benzimidazole fungicides in fortified samples. Incurred potato and banana samples were also analyzed.