蒜苔中咪鲜胺及其代谢物残留检测方法的研究与比较

建立了水解法与QuEChERS法测定蒜苔中咪鲜胺及其代谢物的残留量，并对两种方法进行了比较。在QuEChERS法中，样品经乙腈提取，QuEChERS净化管净化后用气相色谱法测定咪鲜胺及其代谢产物2，4，6-三氯苯酚的含量，基质匹配标准曲线外标法定量；在水解法中，样品经乙腈提取，吡啶盐酸盐水解后，用硫酸磺化，用气相色谱法测定咪鲜胺的含量。结果表明，水解法和QuEChERS法测定的咪鲜胺标准曲线在0.01~2 mg/L范围内均有良好的线性关系，相关系数（r²）均大于0.999。水解法中咪鲜胺的定量限（LOQ）为0.005 mg/kg；QuEChERS法中咪鲜胺的LOQ为0.039 mg/kg、2，4，6-三氯苯酚的LOQ为0.003 mg/kg。在3个不同浓度添加水平下，方法回收率为81.5%~105.4%，相对标准偏差（RSD）为1.3%~6.8%。在测定阳性样品时，水解法可以较为全面地检测出样品中咪鲜胺及其主要代谢物的总量，QuEChERS法可以检测出咪鲜胺及其主要代谢物2，4，6-三氯苯酚的存在形式和各自的含量，两种方法可以互相补充用于蒜苔中咪鲜胺及其代谢物的检测和确证。

Study and comparison of detection methods for prochloraz and its metabolite residue in garlic bolting

Two analytical methods for the determination of prochloraz and its metabolite residues in garlic bolting were established and compared. In the QuEChERS method, the sample was extracted with acetonitrile and purified in a QuEChERS purification tube, and then, the contents of prochloraz and its metabolite 2, 4, 6-trichlorophenol were determined by gas chromatography. The hydrolysis method involved extraction of the sample with acetonitrile, hydrolysis by pyridine hydrochloride, purification with sulfuric acid, and determination of the prochloraz content by gas chromatography. The standard curve in the hydrolysis and QuEChERS methods showed a good linear relationship in the concentration range of 0.01-2 mg/L, and the correlation coefficient (r²) was greater than 0.999. The limit of quantitation (LOQ) for prochloraz in the hydrolysis method was 0.005 mg/kg. The LOQ for prochloraz in the QuEChERS method was 0.039 mg/kg, and that for 2, 4, 6-trichlorophenol was 0.003 mg/kg. At three spiked levels in the sample, the recoveries were 81.5%-105.4%, and the relative standard deviations (RSDs) were between 1.3%-6.8%. In the determination of positive samples, the hydrolysis method can detect the total amount of prochloraz and its main metabolites. QuEChERS method can detect the presence and contents of prochloraz and its main metabolite 2, 4, 6-trichlorophenol. These two methods can complement each other for the detection and confirmation of prochloraz and its metabolites in garlic bolting.