间接光度法测定药物中抗坏血酸

Indirect Photometric Determination of Ascorbic Acid in Drugs

摘要: 在表面活性剂十六烷基三甲基溴化胺存在下,抗坏血酸能定量将铁(Ⅲ)还原为铁(Ⅱ),利用显色剂5-硝基-1,10-菲咯啉建立了间接光度法测定抗坏血酸的方法,在pH 4.6的乙酸-乙酸钠缓冲溶液中,铁(Ⅱ)-5-硝基-1,10-菲咯啉络合物的最大吸收峰位于502 nm波长处,抗坏血酸的质量浓度在0.1~2.0 mg·L-1范围内符合比耳定律,表观摩尔吸光率为2.48×104L·mol-1·cm-1.方法用于维生素C片剂及注射液中抗坏血酸含量的测定,与碘量法对照,两方法所得结果相符.

Abstract: In an acetate buffer of pH 4.6,and in the presence of CTMAB,Fe(Ⅲ) ion was quantitatively reduced by ascorbic acid to Fe(Ⅱ) ion.A colored coordination complex was formed between the Fe(Ⅱ) ion and 5-nitro-1,10-phenanthroline reagent,with its absorption maximum at 502 nm,and value of molar absorptivity (ε502) 2.48×104L·mol-1·cm-1.Beer′s law was obeyed in the range of 0.1-2.0 mg·L-1 of ascorbic acid.Samples of vitamin C tablets,chewing tablets and injection were analyzed for their ascorbic acid content by the proposed method,giving results in consistency with those obtained by the iodi metry