亚铁氰化钾阻抑光度法测定药剂中抗坏血酸

Spectrophotometric determination of ascorbic acid in medicine with potassium ferrocyanide

目的建立亚铁氰化钾阻抑光度法测定药剂中抗坏血酸的新方法。方法在醋酸介质中,Fe^(3+)与K_4[Fe(CN)_6]反应生成可溶性普鲁士蓝,抗坏血酸具有还原性,能将Fe^(3+)定量还原为Fe^(2+),有效阻止普鲁士蓝的生成,根据Fe^(3+)与K_4[Fe(CN)_6]反应生成可溶性普鲁士蓝的吸光度下降值(△A)与还原性药物浓度之间的定量关系,间接测定出抗坏血酸的含量。结果选定条件下,抗坏血酸在0.45μg/ml^16μg/ml时在特定波长处与吸光度下降值(△A)呈线性关系,相关系数(r)=0.998 4,检出限为0.15μg/ml,相对标准偏差(RSD)分别为1.02%、1.97%(n=6)。结论该方法操作简便、快速准确、重现性好,用于药物中抗坏血酸含量的测定,结果令人满意。

Objective A method of potassium ferrocyanide inhibitory spectrophotometry was established to determine the concentration of ascorbic acid in medicine. Methods Fe-（3＋）can reacted with K_4[Fe（ CN）_6]in acetic acid solution to form soluble prussian blue. While the reducing ascorbic acid can reduced the Fe-（3＋）to Fe-（2＋）,thus,which prevented the formation of prussian blue. and according to the quantitative relationship between drug concentration and the decrease of absorbance value of prussian blue produced by the reaction of Fe-（3＋）and K_4[Fe（ CN）_6],the concentration of ascorbic acid could be calculated indirectly. Results Under the selected conditions,a good linear relationship was obtained when the range of ascorbic acid was among 0. 45μg /ml- 16 μg /ml between it and the decrease of absorbance value（ △A）,with correlation coefficient of 0. 998 4. The detection limit and relative standard deviations（ RSDs） were 0. 15 μg / ml and 1. 02%,1. 97（ n = 6）,respectively. Conclusion The method is simple,rapid and accurate with good reproducibility,which can be used to measure the concertration of ascorbic acid in medicine with satisfactory results.