核黄素的光降解及维生素C对核黄素的保护效应(英文)

PHOTODEGRADATION OF RIBOFLAVIN AND THE PROTECTIVE EFFECT OF ASCORBIC ACID

目的调查核黄素的光降解及维生素C对核黄素的保护作用。方法用荧光光谱仪记录待测液体的吸收光谱和荧光光谱并通过光谱分析来研究核黄素的光降解过程。结果核黄素吸收紫外和蓝色光。其吸收光谱在223nm、267nm、374nm、445nm处有4个峰值。在445nm处峰值随光照的时间的增加而不断降低。当加入维生素C时降低速度有所减缓。当用375nm光激励时,其荧光光谱分别在460nm和528nm处出现随光照时间的不断增加而降低的两个峰值。结论紫外和蓝色光可使核黄素发生光降解,维生素C在一定程度上可以降低它的降解程度。

Objective Investigate the photodegradation of riboflavin an Methods A UV/VIS spectrophotometer and a luminescence spectrometer were d effect of antioxidant ascorbic acid used to record the absorption and fluorescence spectra of riboflavin and the product of photodegradation. Results Riboflavin absorbs radiation in the UV and blue light region. It had absorption peaks at 223 nm （UVC）, 267 nm （UVB）, 374 nm （UVA）, 445 nm （blue）. The most absorbance decrease was happened around 445 nm. When ascorbic acid was presented, the degradation rate decreased. The emission spectra of riboflavin had a peak at 528 nm with excitation wave at 375 nm and at 445 nm before and after blue light exposure. This peak decreased when irradiated. Another small increasing peak appears at 460 nm when excited by 375 nm. Conclusion Riboflavin degrades under blue light and UVA exposure. The absorption peaks are found around 220 nm, 265 nm, 374 nm and 445 nm; Riboflavin is fluorescent, with excitation peaks at 375 nm and 445 nm and an emission peak at 528 nm;Ascorbic acid has concentration de- pendent protection effect to riboflavin.