流动注射-褪色光度法测定药物中维生素C含量

Determination of vitamin C by in flow injection discoloring spectrophotometry

目的:建立流动注射-褪色光度法测定药物中维生素 C 含量的方法。方法:盐酸介质中,维生素 C(Vc)能使 Fe^(3+)与SCN^-红色络合物褪色,且络合物吸光度减小与 Vc 用量成线性关系,流动注射体系测定褪色前后络合物吸光度。测定波长:480 nm,流速:6.7 mL·min^(-1)。结果:在优化条件下,Vc 浓度在0.0～6.4μg·mL^(-1)范围内,符合朗伯-比耳定律,线性方程为△A=-0.00406+0.08347C,r=0.9995,检出限(S/N=3)为0.18μg·mL^(-1),流通量为72样/h。使用本法测定了 Vc 片剂、注射液及银翘片中的 Vc,结果与药典法一致。结论:本法快速准确,可用于 Vc 的批量分析。

Objective： To establish a method for determination of vitamin C by FIA - discoloring spectrophotometry. Method ： In the medium of HCl, a new FIA - discoloring spectrophotometry for the determination of Vc was proposed based on the discoloring effect of Vc on the reaction between Fe^3 ＋ and SCN - and the absorbance drop of red complex of Fe^3 ＋ and SCN - was proportional to the amount of Vc. The detection wavelength was 480 nm and flow rate was 6.7 mL· min^ - 1. Results. Under the optimum conditions, the linear range and detection limit was 0. 0 - 6.4 μg · mL^ - 1 （ r = 0. 9995 ） and 0. 18 μg · mL^ - 1 respectively. The sample throughput was 72 samples/h. The proposed method has been successfully applied to the determination of Vc in the Vc tablets, Vc injection and cimetidine tablets. Conclusion：The method is simple, accurate and very suitable to determine Vc in batches.