摘要:本课题对徐州市售茶叶中重金属铅、镉、铬、铜污染进行了细致的研究。分别用干法灰化、湿法消解、微波消解方法对茶叶样品进行预处理，比较它们的优缺点，最后选用微波消解进行样品处理，用石墨炉原子吸收分光光度计测量，得到徐州市市售茶叶中重金属含量，再进行比较确定污染状况，制定科学有效的治理方案。
实验选取了具有代表性且常见的红茶、绿茶、花茶和乌龙茶4种茶系，共60种茶叶样品。实验表明，干法灰化对元素的破坏性大，湿法消解污染较大，最后采用微波消解法处理。实验数据显示，所测的60种茶叶样品中重金属Cu、Pb、Cr、Cd的含量均未超标。同种茶系中不同茶叶的重金属含量，除茶包中的含量明显高于其他同茶系茶叶，其他茶叶的重金属含量相对稳定且未超标。不同茶系中，Cu的平均含量从高到低依次是红茶＞绿茶＞花茶＞乌龙茶；Pb的平均含量从高到低依次是乌龙茶＞红茶＞花茶＞绿茶；Cr的平均含量从高到低依次是绿茶＞红茶＞花茶＞乌龙茶；Cd的平均含量从高到低依次是红茶＞花茶＞乌龙茶＞绿茶。徐州茶叶市场处于一个相对安全且稳定的状态。
关键词 茶叶；微波消解；重金属；原子吸收
Abstract:This paper makes a detailed study on the heavy metal lead in tea sold in Xuzhou, cadmium, chromium, copper pollution. The raw material was pretreated by dry ashing, wet digestion, microwave digestion method, comparing their advantages and disadvantages, the final selection of microwave digestion for sample processing, spectrophtometer measured by graphite furnace atomic absorption, heavy metal content in tea is sold in Xuzhou City, and then compared to determine the pollution situation, formulate scientific and effective control plan.
The experiments selected four representative and common teas which contain black tea, green tea, jasmine tea and oolong tea. There is a total of 60 kinds of tea samples. The experiments show that the the dry ashing destructive elements, the wet digestion pollution, last by microwave digestion treatment. The experimental data shows that the 60 kinds of tea samples measured heavy metals Cu, Pb, Cr, Cd's content were not excessive. With the heavy metal content of different tea in the tea-growing system, with the exception of content in tea bags was significantly higher than with tea tea, other tea heavy metal content is relatively stable and not excessive. Different tea lines, the average content of Cu the descending order of black tea> green tea> scented tea> oolong tea; the average content of Pb in descending order oolong tea> black tea scented tea> green tea; CR average content order green tea> black tea scented tea> oolong tea; the average content of the CD in descending order black tea scented tea> oolong tea> green tea. Xuzhou tea market is in a relatively safe and stable state.
Keywords Tea Microwave digestion Heavy metal Atomic absorption
