基于细菌纤维素的毛细管电泳法同时测定果蔬中3种苯并咪唑类杀菌剂

建立了高效毛细管电泳同时测定果蔬中3种常见的苯并咪唑类杀菌剂(甲基硫菌灵、多菌灵和苯菌灵)的分析方法。以细菌纤维素(BC)为电泳缓冲液添加剂来提高毛细管电泳的分离能力。系统考察了检测波长、缓冲液离子强度、缓冲液pH、分离电压及BC添加量对3种苯并咪唑类杀菌剂分离效果的影响。最终的优化条件:H3BO3/Na2B4O7缓冲液(4 mmol/L,pH 9.0);BC添加质量分数0.3%;运行电压15 kV;分离柱温25℃;检测波长275 nm。3种苯并咪唑类杀菌剂在8 min之内可实现基线分离及准确定量。结果显示:3种苯并咪唑类杀菌剂在各自线性范围内线性关系良好,相关系数(r2)≥0.997;检出限为5.0~10.0μg/L;保留时间及峰面积的日间相对标准偏差(n=5)分别为0.82%~1.0%和2.4%~2.9%。该法用于葡萄、番茄及黄瓜中3种苯并咪唑类杀菌剂的测定,加标回收率为93.5%~103.0%,RSD≤8.0%。该法可作为果蔬中甲基硫菌灵、多菌灵和苯菌灵同时检测的有效手段。

Simultaneous determination of three benzimidazole fungicides in fruits and vegetables by capillary electrophoresis based on bacterial cellulose

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.