超高效液相色谱-串联质谱法测定茶叶中氯噻啉的残留量

Determination of Imidaclothiz Residue in Tea by Ultra-Performance Liquid Chromatography Tandem Mass Spectrometry

[目的]建立一种超高效液相色谱-串联质谱测定茶叶中氯噻啉残留量的方法。[方法]样品用乙腈匀质提取,经GC-e/NH2柱去除杂质,经C18液相柱分离后,用电喷雾离子化-串联质谱测定。[结果]在12.5-100.0滋g/L质量浓度范围内,氯噻啉工作曲线相关系数（R2）为0.994 5,仪器最小检出量为5.98×10^-13 g。在0.025、0.25、2.50 mg/kg添加水平下,茶叶中氯噻啉回收率在94.66%-96.30%之间,相对标准偏差小于8.0%,方法最低检出限为0.99×10^-3mg/kg。采用该方法对实际样品进行测定,均未检出氯噻啉残留。[结论]方法准确、快速、稳定,能够满足实际残留检测的需要。

[Aims] An ultra-performance liquid chromatography tandem mass spectrometry（UPLC-MS/MS） method for determination of imidaclothiz in tea was developed and validated. [Methods] The sample was homogenized by acetonitrile and cleaned-up by GC-e/NH2 SPE column, finally determinated by UPLC-MS/MS（ESI＋） coupled with Thermo Hypersil GOLD C18. [Results] The Results indicated the correlation coefficient（R2） of standard working curve of imidaclothiz in tea matrix（12.5-100.0 μg/L） was 0.994 5, and the limit of detection（LOD） was 5.98×10^-13 g. The recoveries of imidaclothiz at levels of 2.50, 0.25 and 0.025 mg/kg were between 94.66 and 96.30%, with relative standard deviations（RSDs） below 8.0% and limit of quantitation（LOQ） 0.99×10^-3mg/kg. For validation, 8 samples including green tea, black tea and oolong tea were determinated by this method. The results showed no imidaclothiz residues in these samples were found. [Conclusions] The rapid, stable and good precision of the method make it be well suitable for determination of imidaclothiz in tea.