褪色光度法测定几种市售橙汁饮料中维生素C含量

DETERMINATION ON VITAMIN C IN SEVERAL AVAILABLE ORANGE JUICES BY DEPIGMENTATION SPECTROPHOTOMETRY

本文旨在建立一种仪器设备费用不高,操作过程简单,测定准确度较高,能够在大多基础实验室普及的市售橙汁饮料维生素C测定方法。本文先是确定采用高锰酸钾作为显色剂和反应物,建立硫酸、维生素C、高锰酸钾体系褪色光度法测定市售橙汁饮料维生素C,然后通过单因素分析确定实验的最佳条件。维生素C浓度在0~16μg/ml范围内与溶液的褪色程度（△A）服从朗伯·比尔定律,最小检出限为0.00214μg/ml,相对标准偏差为0.81%~0.89%,回收率为94.0%~101.0%。

A new method has been developed for determination of the Vitamin C in several orange juices based on the KMnO4 depig- mentation after adding Vitamin C. The maximum absorption is at 526 nm, the apparent molar absorptivity is 1.35 × 10^4L · mol - 1 · cm - 1, and the linear range of determination is 0 - 16μg/ml. The determination limit （3σ） was 0. 00214μg/ml, RSD was 0.81% 0.89%, and coefficient of recovery was satisfactory. In comparison with traditionary methods of the determination of Vitamin C, the present method is simple, stable, easy to operation, cheaper.