硫氰酸铵-乙醇-水体系萃取浮选铜法间接测定抗坏血酸

Indirect determination of ascorbic acid by extraction-floatation of copper in ammonium sulfate-ethanol-water system

微量Cu（Ⅱ）被抗坏血酸还原成Cu（Ⅰ）后可与SCN^-生成CuSCN沉淀，在乙醇与水分相的过程中，CuSCN被浮选，且抗坏血酸用量和浮选率之间存在良好的线性关系。抗坏血酸的检出限为5×10^-5mol／L。该方法简单、快速、干扰离子少，已成功应用于水果中抗坏血酸的检测。

A small amount of Cu（Ⅱ） is reduced to Cu（Ⅰ） by ascorbic acid,then Cu（Ⅰ） react with SCN^- obtain CuSCN. In the course of phase separation of ethanol from water, CuSCN is floatated, a good linear relationship is observed between the floatation yield （E） of Cu （Ⅱ） and the amount of ascorbic acid. The method is simple ,rapid and suffers little interference from common anions and cations. It has been successfully applied for the determination of ascorbic acid in fruits.