Abstract:

A simple and rapid capillary electrophoresis (CE) method was developed for the determination of trace thiophanate-methyl, carbendazim and benomyl in fruits and vegetables. Herein, bacterial cellulose (BC) was used as additive in running buffer to improve the separation efficiency. CE experimental parameters such as detection wavelength, concentration and pH of the running buffer, separation voltage as well as the contents of BC in running buffer were systematically investigated. Under the optimized conditions, three benzimidazole fungicides could be accurate quantified in 8 min using H₃BO₃/Na₂B₄O₇ (4 mmol/L, pH 9.0) containing 0.3% (mass fraction) BC for background electrolyte, 15 kV for the separation voltage, 25℃ for the column temperature and 275 nm for detection wavelength. Good linearities for the three benzimidazole fungicides were obtained with correlation coefficients (r²) ≥ 0.997. The limits of detection (LODs) of the three benzimidazole fungicides were between 5.0 and 10.0 μg/L. The relative standard deviations (RSDs, n=5) of inter-day were 0.82%-1.0% for retention times and 2.4%-2.9% for peak areas. The proposed method was further applied to determine the residues of the three benzimidazole fungicides in fruits and vegetables. The recoveries were in the range of 93.5%-103.0% with RSDs no more than 8.0%. These results indicated that the proposed method can serve as an efficient tool for the simultaneous determination of the three benzimidazole fungicides in fruits and vegetables.

Key words: bacterial cellulose (BC), benomyl, benzimidazole fungicides, capillary electrophoresis (CE), carbendazim, fruits and vegetables, thiophanate-methyl