萃取催化光度法间接测定痕量抗坏血酸  

Indirect determination of trace ascorbic acid by extraction catalytic spectrophotometry

作　　者：孙登明[1] 

机构地区：[1]淮北煤炭师范学院化学系,淮北235000

出　　处：《分析试验室》2005年第1期1-4,共4页Chinese Journal of Analysis Laboratory

基　　金：安徽省高校自然科学基金资助课题(2001KJ196;2004KJ320)

摘　　要：研究了在pH5.5的HAc NaAc缓冲溶液介质中,利用抗坏血酸活化Fe(Ⅲ)催化H2O2氧化邻氨基酚的显色反应,用萃取平衡控制反应时间和水相中邻氨基酚的浓度及反应程度,通过测量424nm下有机相的吸光度,建立了萃取催化光度法间接测定痕量抗坏血酸的新方法。方法的线性范围为0～50.0μg/L,检出限为6.7×10-7g/L。方法可用于维生素C片和西红柿中抗坏血酸的测定。并对反应机理进行了探讨。A new extraction catalytic spectrophotometric method for the indirect determination of trace ascorbic acid is studied. The method is based on the activation of ascorbic acid on the iron(Ⅲ) catalyzes oxidation of o-aminophenol by hydrogen peroxide in the weak acidic medium at pH 5.5. The reaction time, concentration of o-aminophenol in aqueous phase and degree of reaction are controlled by extraction equilibrium. The absorbance of organic phase is measured at 424 nm. The linear range of the determination is 0～50.0 μg/L. The detection limit is 6.7×10^(-7) g/L. The method has been applied to the determination of trace ascorbic acid in vitamins C tablets and tomatoes with satisfactory results. The reaction mechanism is disscussed.

关 键 词：萃取 催化光度法 抗坏血酸 铁 邻氨基酚 

分 类 号：O657.32[理学—分析化学]