A sensitive determination method for carbendazim and thiabendazole in apples by solid-phase microextraction?high performance liquid chromatography with fluorescence detection

A new analytical method for the determination of carbendazim (MBC) and thiabendazole (TBZ) in apples is reported, based on solid-phase microextraction (SPME) coupling HPLC with fluorescence detection. The main SPME and HPLC experimental conditions were optimized. The apples were first blended and centrifuged. Then, an aliquot of the resulting solution was subjected to SPME on a 60 µm polydimethylsiloxane/divinylbenzene (PDMS/DVB) fibre for 35 min at room temperature with the solution being stirred at 1100 rev min^–1. The extracted pesticides on the SPME fibre were desorbed in the mobile phase into the SPME/HPLC interface for HPLC analysis. The method was linear over the range 0.01–1 mg kg^–1 in apples for both MBC and TBZ, with detection limits of 0.005 and 0.003 mg kg^–1 and correlation coefficients of 0.9995 and 0.9998, respectively. The average recoveries for MBC and TBZ were 91.5 and 92.3% with the relative standard deviations (RSD) of 4.7 and 4.1% at the 0.1 mg kg^–1 level, and 94.6 and 96.1% with RSD of 3.3 and 3.8% at the 0.5 mg kg^–1 level, respectively. The method is simple, sensitive, organic solvent-free and is suitable for the determination of MBC and TBZ in apples.