张云, 李登昆, 刘祥萍, 赵士权. 气相色谱-三重四极杆质谱法结合QuEChERs前处理同时测定茶叶中三氯杀螨醇、溴虫腈、6种拟除虫菊酯类农药[J]. 环境与职业医学, 2020, 37(8): 812-817. DOI: 10.13213/j.cnki.jeom.2020.20108
引用本文: 张云, 李登昆, 刘祥萍, 赵士权. 气相色谱-三重四极杆质谱法结合QuEChERs前处理同时测定茶叶中三氯杀螨醇、溴虫腈、6种拟除虫菊酯类农药[J]. 环境与职业医学, 2020, 37(8): 812-817. DOI: 10.13213/j.cnki.jeom.2020.20108
ZHANG Yun, LI Deng-kun, LIU Xiang-ping, ZHAO Shi-quan. Determination of dicofol, chlorfenapyr, and six kinds of pyrethroids in tea leaves by gas chromatography tandem mass spectrometry combined with QuEChERs pretreatment[J]. Journal of Environmental and Occupational Medicine, 2020, 37(8): 812-817. DOI: 10.13213/j.cnki.jeom.2020.20108
Citation: ZHANG Yun, LI Deng-kun, LIU Xiang-ping, ZHAO Shi-quan. Determination of dicofol, chlorfenapyr, and six kinds of pyrethroids in tea leaves by gas chromatography tandem mass spectrometry combined with QuEChERs pretreatment[J]. Journal of Environmental and Occupational Medicine, 2020, 37(8): 812-817. DOI: 10.13213/j.cnki.jeom.2020.20108

气相色谱-三重四极杆质谱法结合QuEChERs前处理同时测定茶叶中三氯杀螨醇、溴虫腈、6种拟除虫菊酯类农药

Determination of dicofol, chlorfenapyr, and six kinds of pyrethroids in tea leaves by gas chromatography tandem mass spectrometry combined with QuEChERs pretreatment

  • 摘要: 背景

    茶叶中农药残留问题热度一直居高不下,目前鲜见利用气相色谱-三重四极杆质谱法同时测定茶叶中三氯杀螨醇、溴虫腈、6种拟除虫菊酯。

    目的

    采用QuEChERs法进行样品前处理,建立气相色谱-三重四极杆质谱法同时测定茶叶中三氯杀螨醇、溴虫腈、6种拟除虫菊酯残留的方法。

    方法

    准确称取2.0 g茶叶试样于离心管,纯净水浸泡后,乙腈-乙酸振荡提取,无水硫酸镁除水,醋酸钠盐析分层,上层有机提取液加到内含硫酸镁、N-丙基乙二胺、十八烷基硅胶键合相及石墨化炭黑的分散固相净化管中净化离心,净化液氮吹浓缩后加内标环氧七氯B,乙酸乙酯定容,经串联双柱DB-5MS色谱柱分离,进入三重四极杆质谱端进行多反应离子监测模式测定,保留时间及离子对定性,内标法定量测定。60份市售茶叶样品按上述步骤处理后,上机同时测定三氯杀螨醇、溴虫腈、6种拟除虫菊酯农药含量,计算方法的线性范围、检出限、定量限、回收率和精密度。

    结果

    在10~500μg·L-1质量浓度范围内,8种农药工作曲线相关系数均大于0.998,方法的检出限(信号噪音比为3)为0.51~12.93μg·kg-1,定量限(信号噪音比为10)为1.69~43.10μg·kg-1。在低、中、高3个浓度添加水平下(0.150、0.375、1.500 μg·kg-1),方法的回收率在74.4%~110.0%,相对标准偏差范围为2.38%~14.40%(n=7),相对标准偏差均小于20%。茶叶样品中:54份检出混合农药残留,1份检出单种农药残留;氯氟氰菊酯有1份茶叶样品超标,氰戊菊酯有3份样品超标。

    结论

    本研究建立的方法操作简单,快速,适用于大批量茶叶中8种农药残留的快速筛查和定量检测。

     

    Abstract: Background

    The pesticide residues in tea leaves are widely concerned. At present it is rarely reported that gas chromatography tandem mass spectrometry is used to simultaneously determine dicofol, chlorfenapyr, and six kinds of pyrethroids.

    Objective

    This study aims to establish a method for simultaneous determination of dicofol, chlorfenapyr, and six kinds of pyrethroids in tea leaves by gas chromatography tandem mass spectrometry (GC-MS/MS) combined with QuEChERs method for pretreatment.

    Methods

    First, 20 g tea leaves were accurately weighted into a centrifuge tube, soaked in water, shaken and extracted with acetonitrile-acetic acid, dehydrated with magnesium sulfate, and salted with sodium chloride. Second, the upper organic extracts were purified and centrifuged in a disperse solid phase extraction tube containing magnesium sulfate, N-propyl ethylenediamine, octadecylsilane bonded silica gel, and graphited carbon black, concentrated by nitrogen blowing, and then added with internal standard heptachlor exo-epoxide isomer B and ethyl acetate. After DB-5MS column separation, the target chemicals were determined by gas chromatography-tandem mass spectrometry with multireaction monitoring mode, quantified with retention time and ion pairs, and quantified by internal standard method. Retail tea leaf samples were collected to simultaneously determine dicofol, chlorfenapyr, and six kinds of pyrethriods according to the above established method, then the linear ranges, limits of detection, quantitative limits, recoveries, and precisions were calculated.

    Results

    The linear ranges of the selected eight kinds of pesticides were 10-500 μg·L-1, the correlation coefficients were all greater than 0.998, the method limits of detection (S/N=3) were 0.51-12.93 μg·kg-1, the quantitative limits (S/N=10) were 1.69-43.10 μg·kg-1. At three spiked levels of 0.150, 0.375, and 1.500 μg·kg-1, the recoveries were from 74.4% to 110.0%, and the relative standard deviations were from 2.38% to 14.40% (n=7), all less than 20%. Of the collected tea leaf samples, 54 samples were detected positive of mixed pesticide residues, and 1 sample positive of single pesticide residues; 1 samples were unqualified for cyhalothrin, and 3 samples for fenvalerate.

    Conclusion

    The method is easy, fast, and suitable for rapid screening and quantification of the eight pesticides in large quantities of tea samples.

     

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