色谱

色谱 ›› 2018, Vol. 36 ›› Issue (10): 1028-1037.DOI: 10.3724/SP.J.1123.2018.07014

• 研究论文 • 上一篇    下一篇

分散固相萃取-气相色谱-质谱法测定茶叶中18种多氯联苯

刘腾飞1, 杨代凤1, 章雪明2, 毛健1, 董明辉1   

  1. 1. 江苏太湖地区农业科学研究所, 江苏 苏州 215155;
    2. 苏州市农产品质量安全监测中心, 江苏 苏州 215128
  • 收稿日期:2018-07-16 出版日期:2018-10-08 发布日期:2014-08-22
  • 通讯作者: 杨代凤.Tel:(0512)66705835,E-mail:saasydf@163.com
  • 基金资助:

    江苏省食品质量安全重点实验室-省部共建国家重点实验室培育基地开放课题（201603）；苏州市科技计划项目（SNG201622，SNG201644）.

Determination of 18 polychlorinated biphenyls in tea by gas chromatography-mass spectrometry coupled with dispersive solid-phase extraction

LIU Tengfei1, YANG Daifeng1, ZHANG Xueming2, MAO Jian1, DONG Minghui1   

  1. 1. Jiangsu Taihu Area Institute of Agricultural Sciences, Suzhou 215155, China;
    2. Suzhou Agricultural Products Safety and Quality Inspection Center, Suzhou 215128, China
  • Received:2018-07-16 Online:2018-10-08 Published:2014-08-22
  • Supported by:

    Open Project of the Key Lab of Food Quality and Safety of Jiangsu Province-State Key Laboratory Breeding Base(No. 201603); Science and Technology Planning Project of Suzhou City (Nos. SNG201622, SNG201644).

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摘要：

建立了以羧基化多壁碳纳米管（MWCNTs-COOH）和N-丙基乙二胺（PSA）为分散固相萃取吸附剂的前处理净化技术，结合气相色谱-质谱（GC-MS）同时检测茶叶中18种多氯联苯（PCBs）的方法。茶叶样品经正己烷-丙酮（1：1，v/v）超声提取后，通过甲苯溶剂置换，以MWCNTs-COOH和PSA混合吸附剂净化，采用电子轰击离子源、选择离子监测模式测定，以保留时间和特征离子丰度比定性，基质匹配标准溶液外标法定量。考察了提取溶剂及吸附剂种类和用量、提取时间和净化时间对分析结果的影响，优化了气相色谱-质谱条件，并评估了优化实验条件下的方法性能。在最优实验条件下，18种PCBs在5~500 μg/kg范围内线性关系良好，相关系数（r）不低于0.9998；当加标水平为5、10和100 μg/kg时，3种茶叶基质中18种PCBs的平均回收率为90.7%~115.2%，相对标准偏差（n=5）为0.3%~10.9%；方法的检出限为0.3~1.7 μg/kg，定量限均为5 μg/kg。该方法操作简单、快速，准确可靠、灵敏度高，样品净化效果好，可用于不同种类茶叶基质中18种PCBs的测定。

关键词: 茶叶, 多氯联苯, 分散固相萃取, 气相色谱-质谱, 羧基化多壁碳纳米管

Abstract:

A method for the rapid determination of 18 polychlorinated biphenyls (PCBs) in tea by gas chromatography-mass spectrometry (GC-MS) coupled with dispersive solid-phase extraction (dSPE) was developed and evaluated. Carboxylated multi-walled carbon nanotubes (MWCNTs-COOH) and primary secondary amine (PSA) were used as sorbents in pretreatment process. PCBs were ultrasonically extracted from tea samples with hexane-acetone (1:1, v/v), and purified with the mixed sorbents of MWCNTs-COOH and PSA after replacing hexane-acetone by toluene. The PCBs were determined by an electron impact ionization source and selected ion monitoring mode. The analytes were qualitatively confirmed from the retention time and relative abundance ratio of characteristic ions, and quantified by a matrix-matched standard solution. The chromatographic and MS parameters influencing separation and sensitivity were optimized, and major factors affecting the extraction and cleanup efficiency including type and volume of extraction solvent, extraction time, type and amount of cleanup sorbent, and clean-up time were investigated. The performance of the method was evaluated. Under optimum conditions, satisfactory linear relationship was observed with the content of PCBs ranging from 5 to 500 μg/kg, with correlation coefficients (r) no less than 0.9998. The 18 PCBs in three kinds of tea matrices including Biluochun tea, Tieguanyin tea and Pu'er tea were spiked at 5, 10 and 100 μg/kg to evaluate recoveries, which ranged from 90.7% to 115.2% with relative standard deviations (n=5) between 0.3% and 10.9%. The limits of detection and the limits of quantification were 0.3-1.7 μg/kg and 5 μg/kg for each PCB, respectively. The method is simple, rapid, accurate, sensitive and effective, and is suitable for the determination of the 18 PCBs in different kinds of tea.

Key words: carboxylated multi-walled carbon nanotubes (MWCNTs-COOH), dispersive solid-phase extraction (dSPE), gas chromatography-mass spectrometry (GC-MS), polychlorinated biphenyls (PCBs), tea

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