New approach for the simultaneous determination fungicide residues in food samples by using carbon nanofiber packed microcolumn coupled with HPLC

Solid-phase extraction preconcentration system using carbon nanofibers (CNFs) packed microcolumn was developed for the simultaneous determination of the fungicides carbendazim (MBC) and thiabendazole (TBZ) by high performance liquid chromatography (HPLC). CNFs exhibited a good affinity to target analytes. Important influence factors were studied in detail, such as amounts of packing material, sample solution acidity, sample flow rate and volume, eluent flow rate and volume. Under the optimal conditions, excellent linearity was obtained in a range of 2.0-500.0 ng mL−1 with a correlation coefficient of r2 ≥ 0.9964. The limits of quantification and detection were in the range of 1.50-1.80 ng mL−1 and 0.45-0.54 ng mL−1, respectively. The present method was applied to the analysis of fruit, vegetable and juice samples, and the recoveries of analytes were in the range of 96.1-103.5% with the relative standard deviations ranging from 1.27% to 3.90% (n = 3). Intra-day and inter-day repeatability values expressed as relative standard deviation were 1.08-2.74% and 2.82-3.94%, respectively. The results showed that the present method was a simply, convenient and feasible method for the determination of MBC and TBZ in real samples.