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以V_C标品为研究对象,利用荧光分光光度计分别采集了280~350 nm激发波长下的荧光发射光谱,结果表明:V_C溶液的最大荧光峰位于EX310 nm/EM400 nm,VC光谱的二阶导数有4个极值点和3个拐点,分别为:328、345、355、372、395、425、525 nm。通过理论分析,证实395 nm是-OH发生的n→σ*电子跃迁,二烯醇结构π→π*电子跃迁产生的荧光峰由于共轭体系的作用发生红移而位于425、525 nm。分子中的各个荧光团相互叠加且彼此制约,在分子团簇作用和水分子的H键的共同作用下,最终使得V_C溶液在400 nm有最大荧光峰。
The V_C standard was used as the research object. The fluorescence emission spectra were acquired at 280 ~ 350 nm by fluorescence spectrophotometer. The results showed that the maximum fluorescence peak of V_C solution was at EX310 nm / EM400 nm and the second derivative of VC spectrum There are 4 extreme points and 3 inflection points, respectively: 328,345,355,372,395,425,525 nm. Theoretical analysis shows that 395 nm is the n → σ * electronic transition of -OH, and the fluorescence peak of the π → π * electron transition of the dienol structure is located at 425,525 nm due to the red shift of the conjugate system. Each fluorophore in the molecule is superposed on one another and is restricted to each other. Under the combined action of molecular clusters and H bonds of water molecules, the maximum fluorescence peak of V_C solution at 400 nm is finally obtained.