高效液相色谱法测定小麦和大米中辛硫磷残留的快速前处理方法

目的建立高效液相色谱法(high performance liquid chromatography, HPLC)快速检测小麦和大米中辛硫磷残留的快速前处理方法。方法采用单因素实验方法考察了提取溶剂乙腈-水的比例和漩涡振荡提取时间。以C_(18)柱(250 mm×4.6 mm, 5μm)为分离色谱柱,以乙腈-水(80:20,V:V)为流动相,采用等度洗脱方式,紫外检测波长为280 nm。结果最佳前处理条件为:乙腈-水的比例为1:2 (V:V),小麦和大米的振荡时间均为8 min。小麦和大米中的辛硫磷在0.02～5.0 mg/L浓度范围内,线性关系良好,线性回归方程为Y=2.45×10~4X-5.88×10~2(r~2=0.9996),方法最低检出限为0.002 mg/kg,小麦的辛硫磷加标回收率为80.4%～87.0%,相对标准偏差(relative standard deviation, RSD)为1.1%～1.8%;大米的辛硫磷加标回收率为80.4%～85.6%, RSD为1.3%～1.9%。结论该方法具有处理快速省时,操作简单,结果准确等优点,可满足对小麦和大米进行多批次快速检测的要求。

Rapid pretreatment for the determination of phoxim residues in wheat and rice by high performance liquid chromatography

Objective To establish a rapid pretreatment method for the determination of phoxim residues in wheat and rice by high performance liquid chromatography. Methods The ratio of acetonitrile to water and the extraction time by eddy oscillation were investigated by single factor experiment. The chromatographic column was C18 column (250 mm 4.6 mm, 5 m), the mobile phase was acetonitrile-water (80:20, V:V), and the UV detection wavelength was 280 nm. Results The optimum pretreatment conditions were as follows: the ratio of acetonitrile to water was 1:2 (V:V). The oscillation time of wheat and rice was 8 min. Phoxim residues in wheat and rice had good linear relationships in the range of 0.02-5.0 mg/L, the linear regression equation was Y=2.45×104X-5.88×102 (r2=0.9996), the minimum limit detection was 0.002 mg/kg, the recovery rates of phoxim in wheat were 80.4%-87.0%, with relative standard deviation (RSD) of 1.1%-1.8%, and the recovery rates of phoxim in rice were 80.4%-85.6%, with RSD of 1.3%-1.9%. Conclusion This method has the advantages of fast processing, time saving, simple operation and accurate results, which can meet the requirements of rapid multi-batch detection of wheat and rice.