全反射X-射线荧光法分析茶叶中的矿质元素

用全反射X -射线荧光法 (TXRF)分析了江西婺绿和宁红茶的矿质元素含量。结果表明 ,所测茶叶中P、S、K、Ca的含量在 2 4 70～ 30 70 0 μg/g ;Mn、Fe在 2 0 6～ 10 70 μg/g ;Ti、Ni、Cu、Zn、Rb、Sr、Ba在 5 5～ 12 2 μg/g ;Pb含量均小于 4 0 μg/g (干基 )。宁红还表现出 ,品质越好 ,P、Ni、Zn含量越高 ,而K、Ca、Mn、Sr、Ba含量则相反。茶汤中K、Rb、Ni的浸出率为 30 5%～ 86 4% ;P、S、Mn、Cu、Zn、Sr为 11 6 %～ 4 2 4% ;Ca为 7 2 %～ 12 6 % ;Fe为 1 1% -2 6 %。茶汤中Ti、Ba、Pb的含量均低于TXRF法的检测限。宁红茶汤还表现出 ,品质越好 ,K、Ca、Mn、Zn、Rb、Sr的浸出率越高。但红茶汤中的K、Zn、Rb、Ni浸出率明显低于绿茶

Analysis of Mineral Elements in Tea by Total-Reflection X-Ray Fluorescence Method

Total reflection X ray fluorescence (TXRF) method was used to the multielement analysis of Jiangxi Wuyuan green tea and Ninghong black tea.The contents of P,S,K,Ca in the tea leaves ranged 2470～30700 μg/g,that of Mn,Fe 206～1070 μg/g,that of Ti,Ni,Cu,Zn,Rb,Sr,Ba 5 5～122 μg/g,and that of Pb lower than 4 0μg/g(dry mass).The results also showed that the better the quality of Ninghong black tea,the higher the contents of P,Ni,Zn in this tea.However,the contents of K,Ca,Mn,Sr,Ba in it changed with the quality in a reverse trend.The solubility of K,Rb,Ni in the tea infusions ranged 30 5%～86 4%,that of P,S,Mn,Cu,Zn,Sr 11 6%～42 4%,Ca 7 2%～12 6%,Fe 1 1%～2 6%.The concentrations of Ti,Ba,Pb in the infusions were lower than the detected limit of TXRF.The better the quality of Ninghong black tea,the higher the solubilty of K,Ca,Mn,Zn,Rb,Sr in its infusion.Otherwise,the solubility of K,Zn,Rb,Ni in the infusions of black tea is obviously lower than that of green tea.