火焰原子吸收分光光度法测定茶叶中八种金属元素含量

建立了利用火焰原子吸收分光光度法测定3种立顿茶包茶(Camellia sinensis L.)叶中的钙、钾、钠、镁、铁、铜、锌、锰等8种金属元素的含量的方法。利用湿法消化(浓硝酸∶高氯酸=4∶1,V/V)处理样品,通过标准曲线法得到各元素含量,并对样品的回收率进行了测定。在选定的试验条件下,各元素在相应的浓度区间内呈良好的线性关系,相关系数为0.995 9~0.999 6,检测限为0.002~0.008μg/m L,回收率为92.0%~114.8%,相对标准偏差为0.52%~3.33%。结果表明,8种元素在3种茶叶中的含量各不相同,3种茶叶中钠元素和镁元素的含量较接近,绿茶中钾元素及锰元素含量较高,红茶中钙元素、铜元素、铁元素及锌元素的含量较高。该方法测定茶叶中的各种元素操作简便,干扰较少,灵敏度高。

Determination of Eight Kinds of Metal Elements in Teas by Flame Atom Absorption Spectrometry

Determination of Ca,K,Na,Mg,Fe,Cu,Zn,Mn in three kinds of Lipton teas by flame atomic absorption spectrophotometry were established.Samples were with treated wet digestionV(HNO3)∶V(HClO4)=4∶l],and determined by standard curve method.The recoveries were determined as well.Under the selected conditions,all eight kinds of metal elements showed good linearity in their own corresponding concentration ranges,with the correlation coefficients between 0.995 9～0.999 6,the detection limit 0.002～0.008 μg/mL,the recovery rates 92.0％～114.8％,the relative standard deviations 0.52％～3.33％.The results showed that concentrations of eight kinds of metal elements in three kinds of teas were different.Concentrations of Na and Mg were close to each other in these three kinds of teas;concentrations of K and Mn were highest in the green tea,however concentrations of Ca,Cu,Fe,and Zn were highest in the black tea.This method has the advantage of simple operation,less interference and high accuracy.