茶叶中微量元素Cr、Cu、Fe、Mn、Ni、Zn的溶出率及化合态研究

用电感耦合等离子体－光发射光谱法（ＩＣＰ－ＯＥＳ）测定市售茶叶中Ｃｒ、Ｃｕ、Ｆｅ、Ｍｎ、Ｎｉ、Ｚｎ等微量元素的含量及各元素沸水溶出率，平均溶出率分别为Ｃｒ３９．８％、Ｃｕ４２．５％、Ｆｅ８．６％、Ｍｎ４５．５％、Ｎｉ８７．１％、Ｚｎ７１．０％。溶出率随浸泡次数增加而降低，总溶出量中８０％的Ｃｒ、Ｃｕ、Ｍｎ、Ｎｉ、Ｚｎ及６０％的Ｆｅ在第一次浸泡中溶出。另外测定了６种元素在茶水中的化学形态，其中有机态

Study on the chemical form and extraction rate of Cr, Cu, Fe, Mn, Ni and Zn in tea

The content of Cr,Cu,Fe,Mn,Ni and Zn in the tea comm only available in China market were measured by inductivity coupled plasm a- optical emission spectrometry (ICP- OES) .The extraction rates of the six elements in tea leachate were measured.The solubilitied were39.8% for Cr,42 .5 % for Cu,8.6 % for Fe,45 .5 % for Mn,87.1% for Ni and 71.0 % for Zn.The process of m aking tea leachate affects the elem ents extraction rates.The content of the microelements in tea leave extracts decreasesgradually with the processing. About 80 % of Cr,Cu,Mn,Ni and Zn and 6 0 % of Fe were in the first infusion of tea.Moreover,the chemical forms of six elements were determ ined.The ratios of organic to inorganic forms were 0 .33 for Cr,0 .0 2 2 for Cu,0 .18for Fe,0 .0 0 2 for Mn,0 .0 1for Ni and 0 .18for Zn.It is concluded thatthe six elements from the tea infusion extracted from5 g tea are too little to meetthe recommend dietary allowance (RDA) . Therefore,tea is not a rich food source of Cr,Cu,Fe,Mn,Ni and Zn.