二苯胺磺酸钠褪色光度法测定饮料中还原型维生素C

Determination of ascorbic acid by discoloration spectrophotometry of sodium diphenylamine sulfonate

在硫酸介质中,二苯胺磺酸钠可被过氧化氢氧化生成二苯联苯胺磺酸紫。利用在酸性条件下还原型维生素C(L-VC)对二苯联苯胺磺酸紫的褪色效应建立了褪色光度法测定还原型维生素C的方法。最大吸收波长为780nm,还原型维生素C浓度在0～24μg/ml范围内与溶液的褪色程度(ΔA)服从比耳定律,回收率为94.5%～100.8%

It＇s found that in sulphuric acid medium, sodium diphenylamine sulfonate can be oxidized by hydrogen peroxide and produce two benzene allied purple. In this paper, a new method of determining ascorbic acid by discoloration spectrophotometry is established by using the discoloring effect of ascorbic acid （L-VC） against two benzene allied purple in acidic medium. The maximum absorptive wavelength is 780 nm, Beer＇s Law is obeyed in the concentration of VC from 0 to 24μg/ml with the discoloration degree （ΔA） of system, and the recovery is 94.5% - 100.8%.