电感耦合等离子质谱法分析不同产区信阳毛尖茶中的稀土元素

目的了解不同产区信阳毛尖茶中稀土元素含量和分布状况,并利用稀土元素对茶叶产地进行判别。方法采用微波消解样品前处理结合电感耦合等离子质谱法对信阳产区106个茶叶样品中的16种稀土元素进行测定。结果信阳毛尖茶叶中不同稀土元素含量差异较大,其中Sc、Ce、La、Nd含量较高,平均含量分别为0.4203、0.1118、0.0862、0.0457 mg/kg;不同产区信阳毛尖茶中轻稀土含量均低于重稀土含量,表明茶树在富集轻稀土元素和重稀土元素的过程中存在着差异;相关分析结果显示茶叶中16种稀土之间存在正相关,表明稀土元素在茶叶富集过程中有较强的协同作用。信阳毛尖茶中稀土氧化物的含量范围为0.5417~1.2823mg/kg,低于国家规定的限量标准2.0 mg/kg。结论稀土元素可作为信阳毛尖茶产地识别的重要指标。

Analysis of rare earth elements in Xinyang maojian tea produced in different regions by inductively coupled plasma mass spectrometry

Objective To realize the content of rare earth elements in Xinyang maojian tea produced in different regions and identify the origin characteristics of the tea with the rare earth elements as an indiactor. Methods Sixteen kinds of rare earth elements in 106 kinds of Xinyang maojian tea samples collected from different regions in Xinyang were determined by inductively coupled plasma mass spectrometry (ICP-MS) combined with microwave digestion. Results The content of the rare earth elements was differed significantly in Xinyang maojian tea samples and the content of Sc, Ce, La and Nd was 0.4203, 0.1118, 0.0862, 0.0457 mg/kg, respectively, which were higher than the other elements. The content of light rare earth elements (LREE) in Xinyang maojian tea samples produced in different regions were all below than the heavy rare earth elements (HREE), which showed that there were differences occurred when the LREE and HREE were uptaked by the tea plants. The correlation analysis showed that there were significantly positive correlationships among the 16 kinds of rare earth elements, which indicated that there had synergistic effect occurred when the rare earth elements were enriched by the tea plants. The content of the rare earth oxides was in the range of 0.5417~1.2823 mg/kg, which were all below the limit (2.0 mg/kg) of tea standards in China. Conclusion The content of the rare earth elements is the important index to identify the origin characteristics of Xinyang maojian tea.