正相高效液相色谱法测定梨中5种菊酯类农药多残留

建立正相高效液相色谱方法同时测定梨样品中氯菊酯、甲氰菊酯、氯氰菊酯、溴氰菊酯和高效氯氟氰菊酯5种菊酯类农药残留。采用混合溶剂正己烷-乙酸乙酯(80/20,V/V)提取,在优化的流动相溶剂正己烷-乙酸乙酯(95/5,V/V)及流速1 mL/min,检测波长242 nm条件下,用配备Zorbax Rx-Sil柱、紫外检测器的高效液相色谱仪进行待测组分的分离和测定,检出限范围在0.108~0.193 ng/μL。添加回收率试验结果表明,梨样品中上述5种菊酯类农药加标回收率为74.0%~108.0%,相对标准偏差(RSD%,n=5)为2.4~7.4,其准确度和精密度均达到了农药残留分析的要求。

Determination of Five Pyrethroids in Pear by Normal-phase High Performance Liquid Chromatography

A method for determination of permethrin,fenpropathrin,cypermethrin,deltamethrin and lambda-cyhalothrin residues in pear was proposed by normal-phase high performance liquid chromatography.The pyrethroids in pear sample were extracted by a mixture of n-hexane and ethyl acetate(80/20,V/V).The HPLC operating conditions were Zorbax Rx-Sil column,n-hexane and ethyl acetate(95/5,V/V) as mobile phase with the flow rate of 1 mL/min and UV detection wavelength at 242 nm.The pyrethroids were analyzed by HPLC with UV detector under optimum conditions and quantified by external standard calibration method.The lowest detection limit of the method was 0.108～0.193 ng/μL.The average recoveries of the five pyrethroids ranged or 74.0%～108.0%,and the relative standard deviation(n=5) were 2.4%～7.4%.