Extraction of thiabendazole and carbendazim from foods using pressurized hot (subcritical) water for extraction a feasibility study

Pressurized hot water was used to extract two fungicides, thiabendazole (TBZ) and carbendazim (MBC), from agricultural commodities including banana pulp, whole lemons, orange pulp, mushrooms, and rice at extraction temperatures below 100 degrees C and an extraction pressure of 50 atm. The extraction parameters that were studied include temperature, equilibration time, flow rate, pH, and collection volume. Liquid-liquid partitioning using ethyl acetate was then used to partition MBC and TBZ from the aqueous extractant and concentrate the analytes for final analysis and the determination of recovery. Residues of TBZ were also determined in incurred matrixes which had already been analyzed by another laboratory using validated methodology. Reversed-phase ion-pairing HPLC with UV absorbance and fluorescence detection was used to determine the recoveries of TBZ and MBC from fortified homogenates. Using an extraction temperature of 75 OC, the average recoveries of MBC and TBZ ranged 80.9-100.5% at fortification levels ranging from 0.14 ppm in fresh mushrooms to 10 ppm in whole lemon homogenates. The relative standard deviations were 10% or less.