摘要
适量的碘与淀粉形成稳定的蓝色配合物,加入Vc将部分I2还原成I-,配合物的浓度减少,溶液反应前后吸光度差(ΔA)与加入的Vc含量成正比,据此可以测量样品中Vc的含量。测定时溶液pH值为4.0,最大吸收波长为590nm,回归方程ΔA=0.0036CVc+0.0114,相关系数R2=0.9999,Vc含量在1～7μg/mL范围内与ΔA呈良好的线性关系,测定回收率为99.8%～103.2%之间,RSD=1.5%,结果与碘量法相近。
Iodine and starch could found a blue complex which had maximum absorption wavelength of 590 nm. When Vc was added into the iodide starch system in a acidic condition about pH 4.0, the iodide were reduced to Iodide ions, and the blue complex＇s absorbance would went down. The reduction of absorbance （AA） had good linear relationship with the contents of Vc from 1 Iag/mL to 7 Iag/mL. The linear regression equation is AA=0.0036Cvc＋0.0114 and R2=0.9999, the recovery of the method were 99.8%-103.2%, and relatively standard deviation were 1.5%.
出处
《食品科技》
CAS
北大核心
2013年第3期282-284,共3页
Food Science and Technology
关键词
碘-淀粉体系
褪色光度法
VC
iodide starch system
fading spectrophotomety
Vc
