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基于碳纳米材料改进QuEChERS结合GC-MS/MS检测茶叶中31种农药残留

Improved QuEChERS Method with Carbon Nanomaterials Combined with GC-MS/MS for the Detection of 31 Pesticide Residues in Tea Leaves

  • 摘要:
    目的 建立一种基于碳纳米材料改良分散固相萃取技术(QuEChERS)提高净化效果,并结合气相色谱-三重四级杆串联质谱法(GC-MS/MS)同时测定茶叶中31种农药残留的检测方法。
    方法 茶叶样品粉碎均匀后,利用碳纳米管作为吸附净化填料改良QuEChERS法净化,运用全自动QuEChERS样品前处理系统提取茶叶中的农药残留,用GC-MS/MS外标法定量。并比较了单壁碳纳米管(SWCNTs)、多壁碳纳米管(MWCNTs)以及氨基化多壁碳纳米管(MWCNTs-NH2)3种净化填料以及其在不同使用量情况下的净化效果。
    结果 选用氨基化多壁碳纳米管(MWCNTs-NH2)改进传统QuEChERS填料,建立的GC-MS/MS检测方法检出限为0.02~1.68 μg·kg−1,定量限为0.05~5.61 μg·kg−1;在低、中、高3个水平加标回收率实验中,目标化合物的平均回收率为81.0%~119.7%;相对标准偏差为1.1%~10.0%。31种目标农药在茶叶中均表现出不同程度的基质效应,氯苯甲醚等4种目标农药表现为基质抑制效应,而乐果等27种目标农药表现为基质增强效应。
    结论 该方法自动高效,灵敏度高,全过程耗时少,能有效的节省人力成本,适用于较大批量的茶叶样品检测。

     

    Abstract:
    Objective A detection method based on modified dispersive solid-phase extraction with carbon nanomaterials (QuEChERS) to improve the cleanup effect and combined with gas chromatography-triple quadrupole tandem mass spectrometry (GC-MS/MS) for the simultaneous determination of 31 pesticide residues in tea was developed.
    Method The tea samples were pulverized uniformly and purified by the modified QuEChERS method using carbon nanotubes as adsorption and purification fillers, and the pesticide residues in tea were extracted using a fully automated QuEChERS sample pretreatment system and quantified by GC-MS/MS external standard method. The purification effects of three types of single-walled carbon nanotubes (SWCNTs), multi-walled carbon nanotubes (MWCNTs) and aminated multi-walled carbon nanotubes (MWCNTs-NH2) were compared with each other and in different amounts.
    Result In this study, aminated multi-walled carbon nanotubes (MWCNTs-NH2) were finally selected to improve the traditional QuEChERS filler, and the limits of detection (LODs) of this research method were 0.02~1.68 μg·kg−1, and the limits of quantification (LOQs) were 0.05~5.61 μg·kg−1; The average recoveries of the target compounds at the three levels of spiked recoveries, low, medium and high, were 81.0%~119.7% with the relative standard deviation (RSD) ranging from 1.1% to 10.0%. The target pesticides showed different degrees of matrix effects in tea, and four target pesticides, such as chloroanisole, showed matrix inhibitory effects, while 27 target pesticides, such as lecithromycin, showed matrix-enhancing effects.
    Conclusion The method is automatic and efficient, with high sensitivity, the whole process consumes less time, can effectively save labor costs, and is suitable for the detection of larger batches of tea samples.

     

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