摘要
以2，9-二甲基4，7-二苯基-1，10-邻菲哆啉为显色剂，建立了一种新的间接光度法测定抗坏血酸。在乙醇和pH6．0的乙酸-乙酸钠缓冲溶液中，基于抗坏血酸可以将Cu^2＋还原成Cu^＋，进而Cu^＋与2，9-二甲基4，7-二苯基-1，10-邻菲哆啉生成稳定的桔红色络合物，在其最大吸收波长475nm处测其相对吸光度以测定抗坏血酸。该方法测定抗坏血酸的线性范围为17．6～176μg／25mL，回归方程为A=0．00384C＋0．05426，相关系数为0．99957，摩尔吸光系数ε475=1．963×10^4L·mol^-1·cm^-1，最低检测限为9．73×10^-2μg·mL^-1，同时还测定了抗坏血酸与Cu^＋及显色剂的反应比。
To establish a new method for the determination of ascorbic acid using 2,9-dimethyl-4,7-diphenyl-1,10- phenan-throline as a chromogenic reagent. Ascorbic acid was determined by the new spectrophotometric method based on the formation of copper （ Ⅰ ） -2,9-dimethyl-4,7-diphenyl-1,10-phenan-throline complex which was the product of the redox reaction between ascorbic acid and copper（ Ⅱ ）. The complex was orange and steady. And the absorption maxima of the complex which was between ethanol and acetic acid - sodium acetate solution of pH 6.0 was at 475nm. The linear relationship was found in the range of 17.6 - 176 μg/25 mL. The linear regression equation was A = 0. 003 84C ＋ 0. 054 26 with a linear correlation coefficient of 0. 999 57, molar absorptivities of complex ε475 = 1. 963 × 10^4 L · mol^-1 . cm-1 and detection limit was 9.73 × 10 ^-2 μg · mL^-1. Determination of the reaction ratio of ascorbic acid, copper（ Ⅰ ） and colour reagent were also evaluated in this article. This method to determinate the contents of ascorbic acid was satisfactory.
出处
《武汉工业学院学报》
CAS
2007年第2期32-35,共4页
Journal of Wuhan Polytechnic University
