超级微波消解-电感耦合等离子体质谱法与测汞仪法测定茶叶中总汞含量的比较

Comparison of determination of total mercury content in tea by ultra microwave digestion-inductively coupled plasma mass spectrometry and mercury vapourmeter method

中文关键词:  超级微波  电感耦合等离子体质谱法  测汞仪  汞  茶叶

英文关键词:ultra microwave  inductively coupled plasma mass spectrometry  mercury vapourmeter  mercury  tea

中文摘要:

      目的 比较超级微波消解-电感耦合等离子体质谱法(inductively coupled plasma mass spectrometry, ICP-MS)和测汞仪法测定茶叶中总汞(Hg)的含量情况。方法 第一法采用超级微波进行消解, ICP-MS检测, 外标法定量。第二法为测汞仪法, 无需消解前处理, 采用直接进样方式, 外标法定量。结果 在最优仪器条件下, 超级微波消解-ICP-MS法测定的Hg在0~2 ng/mL范围内线性关系良好, 相关系数为1.0000, 方法检出限为1 μg/kg。方法成功用于40个茶叶样品(包括红茶、绿茶、白茶、黄茶、花茶、乌龙茶、袋泡茶、紧压茶和黑茶)中Hg的测定, 样品加标回收率在95.5%~106.4%之间, 相对标准偏差(relative standard deviation, RSD)均不超过3.86%。测汞仪法测定Hg在0~20 ng范围内线性关系良好, 相关系数为0.9997, 方法检出限为0.05 μg/kg。测汞仪法同样用于40个茶叶中Hg的测定, 样品加标回收率在93.2%～103.7%之间, RSD不超过6.65%。结论 两种测定方法简便快速、准确、灵敏度高, 均能为快速测定茶叶中总汞元素提供有效的分析方法。测汞仪法相对波动较大, 但是能满足检验检测需求。

英文摘要:

      Objective To compare the determination of total mercury in tea by ultra microwave digestion-inductively coupled plasma mass spectrometry(ICP-MS) and mercury vapourmeter method. Methods In the first method, the sample was digested by ultra microwave, detected by ICP-MS and quantified by external standard method. The second method was mercury vapourmeter method, which did not need digestion pretreatment and injected the sample directly, with quantification by external standard method. Results Under optimal instrument conditions, Hg had good linear relationships in the range of 0~2 ng/mL by ultra microwave digestion-inductively coupled plasma mass spectrometry with the correlation coefficient was 1.0000, and the limit of detection was 1 μg/kg. This method was successfully applied to the determination of Hg in 40 tea samples (including black tea, green tea, white tea, yellow tea, flower tea, oolong tea, teabag, squeeze tea and dark tea), and the recoveries were between 95.5%?106.4% with the relative standard deviations no more than 3.86%. Hg elements showed good linear relationships in the range of 0?20 ng by mercury vapourmeter method with the correlation coefficients was 0.9997, and the limit of detection was 0.05 μg/kg. This method was also used for the determination of Hg in the same 40 tea samples, and the recoveries were 93.2%?103.7% with RSD less than 6.65%. Conclusion This two methods are simple, rapid, accurate and sensitive, which can provide effective analytical methods for the rapid determination of total mercury in tea. Mercury vapourmete method fluctuates greatly, but it can meet the requirements of inspection and detection.