多壁碳纳米管QuEChERS-气相色谱法测定茶叶中23 种有机磷农药残留量

建立测定茶叶中23 种有机磷农药残留量的气相色谱检测方法。茶叶样品经丙酮提取后，采用QuEChERS方法前处理，以N-丙基乙二胺（N-propyl ethylenediamine，PSA）、多壁碳纳米管（multi walled carbon nanotubes，MWCNTs）吸附提取液中的干扰组分，净化液经气相色谱测定，基质外标法定量。采用本实验建立的方法，在0.02～1.00?μg/mL范围内，23?种有机磷的线性关系良好，相关系数r大于0.986?5，方法检出限为0.01～0.02?mg/kg，定量限为0.03～0.06?mg/kg。在0.05、0.50、1.00?mg/kg三个添加量的平均加标回收率为81.8%～107.2%，相对标准偏差为1.2%～7.2%。与传统的QuEChERS相比，该方法具有操作简单、快速、试剂用量少、回收率高、准确性强等特点，适合于茶叶中23?种有机磷农药残留量的测定。

Determination of 23 Organophosphorus Pesticide Residues in Tea by QuEChERS Extraction with Multi-Walled Carbon Nanotubes (MWCNTs) Coupled to Gas Chromatography

This study intended to develop a method for the determination of 23 organophosphorus pesticide residues in tea by gas chromatography (GC). The target pesticides in tea were extracted by a modified QuEChERS method with acetone as the solvent, followed by cleanup with N-propyl ethylenediamine (PSA) adsorbent and multi-walled carbon nanotubes (MWCNTs). The quantification was performed by the matrix external standard method. Good linearity was observed for all calibration curves with correlation coefficients (r) > 0.986 5 over the range of 0.02–1.00 μg/mL. The limits of detections (LODs) were 0.01–0.02 mg/kg, and the limits of quantitation (LOQs) were 0.03–0.06 mg/kg. The recoveries at three spiked levels (0.05, 0.50 and 1.00 mg/kg) varied from 81.8% to 107.2%, with relative standard deviations (RSDs) of 1.2%–7.2%. Compared with the traditional QuEChERS method, this method was easy, fast and solvent saving with good recovery and accuracy. Thus, it was suitable for the determination of 23 organophosphorus pesticide residues in tea.