几种茶叶中Pb和Cd含量研究

茶叶溶出物中Pb、Cd含量的测定,讨论的是采用开水浸泡法、超声波萃取法、干法灰化法及湿式消解法处理5种市售茶叶样品,并用火焰原子吸收光谱法测定其含量;结果表明不同茶叶品种中Pb、Cd含量有一定的差异,湿法消解中绿茶溶出的Pb含量超过国家限量标准;湿式消解法除碧螺春外,测得的Pb和Cd含量均高于干灰化法;超声波能萃取出茶叶Cd;5种茶叶品种开水浸泡后茶汤中仅特级花茶(成都)的一泡超过饮用水卫生标准值,二泡、三泡Pb、Cd均未检出,因此弃饮一泡茶基本无Pb、Cd危害。

Research on the Content of Pb and Cd in Some Teas

The detection of Pb and Cd contents in dissolved materials of five commercial teas is conducted by boiling water soaking method, ultrasonic extraction method, dry ashing method, wet digestion method and flame atomic absorption spectrometry, the results show that the contents of Pb and Cd in different teas are different, thai the content of Pb dissolved from green tea by wet digestion method is higher than the limitation of national standard, the contents of detected Pb and Cd dissolved from the teas except Biluochun by wet digestion method are all higher than the detected contents by dry ashing method, that Cd can be extracted by ultrasonic, and that in the five teas, the contents of Pb and Cd dissolved in boiling water only from superfine scented tea （Chengdu） are higher than drinking health standard value in the first tea-soaked water, however, the contents of Pb and Cd were not detected in the second tea-soaked water and the third tea-soaked water, thus, Pb and Cd in the teas can not harm human beings if the first tea-soaked water is given up.