液相色谱-串联质谱法同时测定棉花中乙烯利、噻苯隆和敌草隆药物的残留量

建立了液相色谱-串联质谱(LC-MS/MS)测定棉花中乙烯利、噻苯隆和敌草隆等植物生长调节剂残留的方法。用甲醇-水振摇提取棉花中的这3种农药,液相色谱-串联质谱测定,负离子扫描方式,多反应监测(MRM),每种农药各两对离子进行定性、定量分析。乙烯利和敌草隆在0~10μg/L、噻苯隆在0~1μg/L范围内相关系数(r)均大于0.999。乙烯利和敌草隆的定量限(LOQ)均为40μg/kg,噻苯隆为4μg/kg。分别以各个药物的LOQ、2LOQ和4LOQ浓度水平进行加标回收试验,回收率范围为89.4%~100.2%,相对标准偏差(RSD)为5.7%~11.5%。该方法简便、快速、准确,各项技术指标满足国内外法规的要求,可用于棉花样品中乙烯利、噻苯隆和敌草隆的定性、定量检测。

Simultaneous determination of ethephon,thidiazuron, diuron residues in cotton by using high performance liquid chromatography-tandem mass spectrometry

A method for the determination of ethephon, thidiazuron and diuron in cotton samples has been developed by high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS). The sample was extracted with methanol-water. The separation was carried out on a C₈ column (150 mm×4.6 mm, 5 μm) with methanol-water (6:4, v/v) as mobile phase at a flow rate of 0.4 mL/min, and the injection volume was 20 μL. Then the sample solution was analyzed by HPLC-MS/MS in negative ion mode with multiple reaction monitoring (MRM). There were one precursor/two product ion transitions for each pesticide. The results showed that the working curves were linear in the range of 0-10 μg/L for ethephon and thidiazuron, and 0-1 μg/L for diuron. The correlation coefficients (r) were all over 0.999. The limits of quantitation (LOQ) of ethephon, diuron were 40 μg/kg, that of thidiazuron was 4 μg/kg. The average recoveries varied from 89.4% to 100.2% with the relative standard deviations (RSDs) of 5.7%-11.5% at three spiked levels (LOQ, 2LOQ and 4LOQ). The method is simple, rapid and accurate, and can meet the requirements of the domestic and international legislation. The method adapts to confirm the residues of ethephon, thidiazuron and diuron pesticides in cotton samples.