不完全消解-同位素稀释-电感耦合等离子体质谱法测定茶叶中铅的含量

Determination of lead in tea by incomplete digestion-isotope dilution-inductively coupled plasma mass spectrometry

中文关键词:  不完全消解  同位素稀释  电感耦合等离子体质谱法  茶叶  铅

英文关键词:incomplete digestion  isotope dilution  inductively coupled plasma mass spectrometry  tea  lead

中文摘要:

      目的 建立不完全消解-同位素稀释-电感耦合等离子体质谱法的测定茶叶中铅的含量。方法 在茶叶样品中加入一定量的同位素稀释剂, 然后在较低温(120 ℃)条件下, 利用硝酸(0.5 mL)将样品中的绝大部分有机物去除, 定容后上机测定同位素比值, 并采用同位素稀释法公式计算铅含量。结果 当加入稀释剂的量在0.2~1.0 μg时, 茶叶标准物质GBW10083中铅含量的测定结果均与推荐参考值较为吻合, 且不同添加量之间的样品检测结果标准偏差较小。与国标方法相比, 两者测定的3个样品检测结果均较为接近, 但本法的准确度和精密度更好。结论 该方法适用于茶叶中铅的高准确测定及标准物质的定值。

英文摘要:

      Objective To establish a method for determination of lead in tea by incomplete digestion-isotope dilution-inductively coupled plasma mass spectrometry. Methods A certain amount of isotopic thinner was added to tea samples, and then the most of the organic matter in the sample was removed with nitric acid (0.5 mL) at low temperature (120 ℃). After the constant volume, the isotope ratio was determined on the machine, and the lead content was calculated by the isotope dilution method formula. Results When the amount of isotopic thinner added was 0.2~1.0 μg, the results of the determination of lead content in the tea standard substance GBW10083 were all in agreement with the recommended reference value, and the standard deviation of sample test results was small. Compared with the national standard method, the results of the 3 samples were close to each other, but the accuracy and precision of this method were better. Conclusion This method is suitable for the accurate determination of lead in tea and the calibration of certified reference materials.