典型地区茶叶中天然铀和钍含量分布

Natural Uranium and Thorium Distribution of Teas in Typical Regions

目的掌握我国典型地区茶叶中天然铀钍的含量及其分布水平,建立微波消解-高分辨质谱分析茶叶样品中铀、钍的方法。方法以15个省的20种茶叶为样本,通过微波消解-电感耦合等离子体质谱分析茶叶中铀、钍的含量。结果铀、钍的检出限分别为11、8.0 ng/L,铀、钍的回收率分别介于97.5%～102.0%和96.9%～102.3%。20种茶叶样品铀、钍含量均低于国家标准规定的铀、钍限值1.5和0.96 mg/kg,样品中钍含量普遍高于铀。结论茶叶中铀、钍含量有一定的区域性分布差异,西部地区、中南地区的茶叶铀钍含量略高于华东、华南地区。

Objective To acquire the content and distribution level of natural uranium and thorium in typical regional teas,and establish microwave digestion-high resolution inductively coupled plasma mass spectrometry method to determine uranium and thorium in tea samples.Methods Taking 20 kinds of teas produced in 15 provinces as samples,high resolution inductively coupled plasma mass spectrometry was used to analysize uranium and thorium after microwave digestion.Results The limit of detection for uranium and thorium was 11 ng/L and 8.0 ng/L,respectively.Their recoveries were between 97.5%～102.0% and 96.9%～102.3% for uranium and thorium.Conclusion Uranium and thorium content of teas have some differences in the regional distribution,and teas from the western and south central regions have higher uranium and thorium content than that of east and south regions.