加速溶剂萃取-超高效液相色谱-串联质谱快速测定棉花中残留的8种脱叶剂

采用加速溶剂萃取结合超高效液相色谱-串联质谱(UPLC-MS/MS)技术,建立了一种快速提取和测定棉花中8种脱叶剂(噻苯隆、脱叶磷、甲基苯噻隆、脱落酸、氟酮唑草酯、敌草隆、百草枯、嘧草硫醚)的分析方法。样品经提取、浓缩,乙腈-水溶液(1:9, v/v)溶解,采用Acquity UPLC^® HSS T3柱(50 mm×2.1 mm, 1.8 μ m)分离,以乙腈-0.05%(v/v)甲酸水溶液为流动相,梯度洗脱,电喷雾正离子模式多反应监测,外标法定量。该方法在0.01~0.3 mg/L范围内线性关系良好(r >0.99),在添加含量水平为0.1、0.5、1.0 mg/kg时,平均回收率范围为(84.18±8.04)%~(95.99±6.76)%,相对标准偏差(RSD)为7.04%~10.60%,方法检出限(LOD)为0.8~29 μ g/kg,方法定量限(LOQ)为2.5~96 μ g/kg。该方法操作简便、快捷、灵敏、准确,适合棉花中8种脱叶剂的确证和定量测定。

Determination of eight defoliant residues in cotton by accelerated solvent extraction coupled with ultra performance liquid chromatography-tandem mass spectrometry

A novel method has been developed for the rapid extraction and determination of eight defoliants including thidiazuron, butiphos, methabenzthiazuron, abscisic acid, carfentrazone-ethyl, diuron, paraquat, and pyrithiobac-sodium in cotton by accelerated solvent extraction (ASE) coupled with ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). The defoliants in cotton were extracted by ASE and the extracts were dried by a rotavapor, then redissolved in the solvents of acetonitrile and water (1:9, v/v). The chromatographic analysis was performed on an Acquity UPLC^® HSS T3 column (50 mm×2.1 mm, 1.8 μ m) by a gradient elution employing of acetonitrile and 0.05% (v/v) formic acid as mobile phases. The analytes were detected by electrospray ionization (ESI) tandem mass spectrometry with multiple reaction monitoring (MRM) in positive ion mode. Good linearities (r >0.99) were observed between 0.01 and 0.3 mg/L for all the compounds. The recoveries and relative standard deviations (RSDs) were obtained by spiking untreated samples with the eight defoliants at 0.1, 0.5 and 1.0 mg/kg. The average recoveries of the eight defoliants were from (84.18±8.04)% to (95.99±6.76)%. The precision values expressed as RSDs were from 7.04% to 10.60% (n=6). The limits of detection were 0.8-29 μ g/kg and the limits of quantification were 2.5-96 μ g/kg for the analytes. The results showed that the method is simple, rapid, sensitive and accurate, and is suitable for the quantitative determination and confirmation of the eight defoliants in cotton.