微波消解-电感耦合等离子发射光谱法测定茶树体中重金属镉和铬

Determination of Heavy Metals Cd and Cr in Tea Plant by Microwave Aided Digestion and Inductively Coupled Plasma-Atomic Emission Spectrometry

采用微波消解处理样品，以等离子发射光谱法测定茶树体中重金属元素镉和铬。结果表明，镉和铬在茶树体内的含量因部位不同而有差异，由高到低，铬的分布次序为：吸收根〉老叶〉生产枝〉嫩叶〉嫩果，镉的分布次序是：吸收根、生产枝〉老叶〉嫩叶〉嫩果。在优化的实验条件下，方法的检出限（n—11）镉为0．0037μg／ml，铬为0．0024μg／ml；回收率为98％～104％，相对标准偏差小于1．05％，茶叶标准物质的分析结果与所给参考值基本一致。本实验方法操作方便、分析速度快、结果准确。

A method using inductively coupled plasma-atomic emission spectrometry for the determination of heavy metals Cd and Cr in tea plant was described. The samples were decomposed by microwave aided digestion. The results indicated that the quantity of heavy metals such as CA and Cr varied greatly in different organs of the tea plant. The distribution of Cr could be sequenced as： absorbing roots 〉 mature leaves 〉 stems 〉 tender leaves 〉 tender fruits. And the distribution of CA could be sequenced as： absorbing roots, stems 〉 mature leaves 〉 tender leaves 〉 tender fruits. Under the optimum conditions, the detection limits （n=11） of CA and Cr were 0. 003 7 μg/mL and 0. 002 4 μg/mL respectively. The recoveries were between 98% and 104%. The relative standard deviations were smaller than 1.05%. The analytical results of standard reference material of tea （GBW 07605） were almost in agreement with the certified values. The method is efficient, accurate and easy to operate.