[关键词]
[摘要]
本文对茶叶中的11种有机氯和拟除虫菊酯类农药残留量进行了同时快速分析。通过简单的样品前处理方法,将茶样与吸附剂充分研磨后,进行柱层析净化预分离,最后经气相色谱检测。文中分别对吸附剂、层析柱和洗脱剂等条件进行了详细考察,优化的方法为:1.0 g茶样浸润后与4.0 g中性Al2O3吸附剂充分研磨,混合物装入预填2.0 g无水Na2SO4+2.0 g Florisil+0.1 g活性炭的自制层析柱净化预分离,以20 mL乙酸乙酯:正己烷(2:3,V/V)洗脱;该法线性范围为0.1~2.0 mg/L,相关系数(r)大于0.9962(除了氟氯氰菊酯和氯氰菊酯),检出限(LOD)在0.0000321~0.1451379 ng之间,样品加标回收率(R)在68.44%~119.20%,不同加标级别回收率结果的相对标准偏差值(RSD)均低于14.73%。此外,对茶样的基质干扰(ME)问题进行了详细讨论,并采用基质匹配校准曲线法(MC)有效解决ME问题。经实验验证,该方法快速、准确、简便、环保,适用于茶叶中农残的同时、快速分离与分析。
[Key word]
[Abstract]
Eleven types of organochlorine and pyrethroid pesticides in tea samples were analyzed simultaneously and rapidly in this study. Using a simple pretreatment method, the tea samples were fully ground with the adsorbent, and then the matrix was purified by column chromatography followed by detection using gas chromatography (GC). Adsorbent, column, and eluent conditions were investigated, and the optimized conditions were as follows: 1.0 g of sample immersed in water was combined completely with 4.0 g of neutral aluminum oxide, and the mixture was transferred into a self-made glass column containing 2.0 g of anhydrous sodium sulfate, 2.0 g of Florisil, and 0.1 g of activated carbon for purification and pre-separation. The combined sample was then eluted with 20 mL of ethyl acetate and n-hexane (2:3, V:V). For this method, the linear range of the calibration curves was between 0.1 mg/L and 2.0 mg/L, the coefficients of determination were ≥0.9962 for all target analytes except cyfluthrin and cypermethrin, and the limit of detection ranged from 0.0000321 ng to 0.1451379 ng. The recoveries ranged from 68.44% to 119.20%, and the relative standard deviations of the recovery results at different spiking levels were lower than 14.73%. In addition, the matrix effect (ME) issue in the tea sample was investigated in detail, and the method of matrix-matched calibration was applied to solve the ME issue effectively. This developed method is fast, accurate, simple, and environmentally friendly, and is suitable for the simultaneous and rapid separation and analysis of various pesticide residues in tea.
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[基金项目]
国家自然科学基金资助项目(31471706);园艺学优势特色重点学科开放基金重点项目(2014YYX006)