茶叶中镉、铅、砷的浸出规律及快速测算方法研究

The Leaching Rules and Rapid Measurement of Cadmium, Lead and Arsenic in Tea

摘要:

为明确茶叶中镉、铅、砷的浸出规律，探索茶叶中相应重金属元素的快速测算方法，分别采用微波消解和沸水浸提方法进行前处理，运用电感耦合等离子体质谱仪（ICP-MS）测定了茶叶、茶水和茶渣中的镉、铅、砷的含量，研究了3种元素的浸出规律及快速测算方法。结果表明，所测茶叶中镉、铅、砷的含量均未超过国家限定标准。在本研究提取条件下，镉、铅、砷三种元素在浸提20 min茶水中的含量与其在茶叶中的含量均呈线性关系，镉的线性方程为Y=7.40623X+0.0235（r=0.9999），铅的线性方程为Y=5.44998X+0.03008（r=0.9935），砷的线性方程为Y=2.25405X+0.01115（r=0.9822）。因此，可以通过测定茶水中的镉、铅、砷含量来评估茶叶中的镉、铅、砷总量，以实现对茶叶中镉、铅、砷含量的快速测算；本研究明确了镉、铅、砷的浸出规律，提供了一种快速提取和检测茶叶镉、铅、砷含量的新方法。

Abstract:

In order to clarify the leaching regularity of cadmium (Cd), lead (Pb) and arsenic (As) in tea, and to explore a fast method for measuring these heavy metals, microwave digestion and boiling water leaching was used for pre-treatment. Then the content of Cd, Pb and As in tea water, tea residue and tea was determined by inductively coupled plasma mass spectrometer (ICP-MS), respectively, to explore the leaching rules of these three elements and develop a rapid determination method. The results showed that the content of Cd, Pb and As in tea did not exceed the corresponding national standard of China. Under the extraction conditions in this study, the contents of Cd, Pb and As in tea water soaked 20 minutes all have a linear relationship with those in tea, and the linear equation of Cd, Pb and As is, Y=7.40623X+0.0235 (r=0.9999), Y=5.44998X+0.03008 (r=0.9935), and Y=2.25405X+0.01115 (r=0.9822), respectively. Therefore, the total amount of Cd, Pb and As in tea can be assessed by measuring the content in tea water, fulfilling the rapid measurement of Cd, Pb and As in tea. This study clarified the leaching rules of Cd, Pb and As in tea, and provided a method for rapid pre-treatment and determination of Cd, Pb and As in tea.