提出了用高效液相色谱法测定苹果中四螨嗪的残留量.将试样与丙酮混合,匀浆并离心分离,使四螨嗪溶于丙酮中,收集上层澄清液,加入20 g·L-1 Na2SO4溶液150 mL后,用二氯甲烷萃取.萃取液在40 ℃蒸发至干,加入甲醇-二氯甲烷(1+99)混合液溶解残渣,所得溶液经Sep-PakVac氨基小柱净化,用上述甲醇-二氯甲烷溶解淋洗,淋出液经吹氮蒸干,用定量的甲醇-二氯甲烷溶解残渣,此溶液用于高效液相色谱法测定.测定中采用Zorbax SB C18不锈钢柱作为色谱柱,用甲醇-水(75+25)溶液作流动相,在273 nm波长处用光电二极管阵列检测器检测.四螨嗪质量浓度在0.35~14 mg·L-1之间与其相应的峰面积值呈线性关系,方法的测定下限(10S/N)为0.05 mg·kg-1.在3个不同浓度水平作回收试验,测得回收率在90.0%~92.0%之间,相对标准偏差(n=6)在2.1%~3.8%之间.

HPLC was applied to the determination of residual clofentezine in apples.Sample of apple was mixed and pulpfied with acetone,and centrifuged to dissolve clofentezine in the solvent.The supernatant solution was collected and extracted with dichloromethane after addition of 150 mL of 20 g·L-1 Na2SO4 solution.The extract was evaporated to dryness at 40 ℃,and the residue was taken up with methanol-dichloromethane (1+99) mixture.The solution was then purified by passing through the Sep-PakVac Amino micro-column and eluted with methanol-dichloromethane (1+99) mixed solvent.The eluate was evaporated to dryness by blowing with nitrogen,and dissolved with a definite volume of the mixed solvent eluant.The solution obtained was used for HPLC determination.Agilent Zorbax SB C18 stainless steel column was used as chromatographic column,and methanol-water (75+25 by vol.) solution was used as mobile phase in the HPLC analysis with photodiode array detection at 273 nm.Linear relationship between values of peak area and concentration of the insecticide was found in the range of 0.35-14 mg·L-1 with determination limit (10S/N) of 0.05 mg·kg-1.Recovery was tested at 3 concentration levels,giving values of recovery over the range 90.0%-92.0% and RSD′s (n=6) over the range 2.1%-3.8%.