气相色谱法快速测定茶叶中有机氯、拟除虫菊酯和有机磷农药残留

Rapid determination of multi-residues of organochlorine, pyrethroid and organophosphorus in tea by gas chromatography

中文关键词:  有机氯农药  拟除虫菊酯农药  有机磷农药  QuEChERS  气相色谱法  茶叶

英文关键词:organochlorine  pyrethroid  organophosphorus pesticides  dispersive solid-phase extraction  gas chromatography  tea

中文摘要:

      目的 建立QuEChERS提取净化结合气相色谱技术同时测定茶叶中有机氯、拟除虫菊酯和有机磷66种农药残留的方法。方法 20 mL乙腈(含1%乙酸)提取溶剂与5 g干燥茶样混匀后, 加入4 g无水氯化钠和1 g乙酸钠, 旋涡振摇2 min后超声提取20 min, 离心(8000 r/min、5 min), 吸取上清液(10 mL)与净化剂(250 mg PSA、250 mg GCB、1 g MgSO4)旋涡混合2 min后离心(8000 r/min、5 min), 上清液经浓缩复溶后一部分直接注入气相色谱-电子捕获检测器检测, 另一部分经气相色谱-火焰光度检测器检测。结果 通过对提取溶剂种类和净化剂用量等进行优化, 添加水平为0.05~0.20 mg/kg时, 回收率在73.75%~117.18%之间, 精密度在0.36%~9.29%之间, 线性范围在0.02~4.0 mg/kg之间(R2＞0.99), 检测限在0.001~0.024 mg/kg之间, 定量限在0.003~0.08 mg/kg之间, 基本满足国内外对茶叶中农药最低残留量的标准要求。结论 本方法简便快速, 准确性好, 成本低, 已用于市面上销售的茶叶产品中有机氯、拟除虫菊酯和有机磷类农药残留测定, 结果均低于国家标准GB2763-2014中规定的最大残留量要求。

英文摘要:

      Objective Gas chromatography (with FPD/ECD detector) was applied to the rapid determination of 66 organochlorine, pyrethroid and organophosphorus pesticides residues in tea with sample pretreatment using QuEChERS method. Methods For extraction of pesticide residues, 5.0 g dry samples were dissolved in 20 mL of acetonitrile (containing 1% acetic acid), and then vortex-mixed with 4 g of NaCl and 1 g of NaAc. After 20 min of ultrasound extraction, samples were centrifuged with 8000 r/min for 5 min. Then 10 mL su-pernatant was taken and vortex-mixed for 2 min after the addition of 250 mg of PSA, 250 mg of GCB, 1 g of MgSO4 and centrifuged with 8000 r/min for 5 min. After high speed centrifugation, nitrogen flushing concentration, and filtration, the samples were detected by GC-FPD and GC-ECD. Results Under the optimized conditions, the average recoveries of the method ranged from 73.75% to 117.18% at the fortification level of 0.05?0.20 mg/kg with RSD of 0.36%~9.29%. The linear ranges were 0.02~4.0 mg/kg (R2＞0.99), limits of detection (LOD) were 0.001~0.024 mg/kg, and limits of quantitation (LOQ) were 0.003~0.08 mg/kg. Conclusion The method is simple, rapid, accurate and low-cost with few impurity disturbs and it is suitable for the detection of organochlorine, pyrethroid and organophosphorus pesticides in tea. The detection results of all organochlorine, pyrethroid and organophosphorus pesticides residues are under the maximum residue limits of GB 2763-2014.