[Fluorescence spectra of ponceau-4R].

The fluorescence spectra of ponceau 4R induced by 220-400 nm light were studied in the present paper. The result shows that ponceau 4R has four obvious fluorescence spectral peaks respectively located at 420, 530, 635 and 687 nm, each of these fluorescence spectral peaks has different best induced light, and the corresponding fluorescence spectra were listed. It was considered that this fluorescence comes from the transition n --> pi* of n electrons in the -OH and pi* --> pi of pi electrons in the naphthalene. The fluorescence spectral peaks at 420 nm come from the transition n --> pi* and the other three fluorescence spectral peaks come from pi* --> pi. But the intensity of the four fluorescence spectral peaks changes differently with the excited wavelength This paper attempted to give the expression of the four fluorescence spectral peaks based on the microcosmic mechanism. The reason for that ponceau 4R has complex fluorescence characteristic is that ponceau 4R not only has big and conjugate structure such as naphthalene and provides electron group -OH which can intensify its ability to emit fluorescence, but also absorbs electron group such as N=N which can depress its ability to emit fluorescence. Investigation on the fluorescence spectra and its characteristics will contribute to the study on the fluorescence spectra of other azo pigment and help find a new way for checking food safety.

[Study of 1-butanol absorption and fluorescence spectra induced by UV-light].

The absorption and fluorescence spectra of 1-butanol solution induced by UV-light and its characteristics were studied experimentally and theoretically. The authors found that 1-butanol solution shows a good absorption in 190-250 nm, and fluorescence was detected when excited by 210-250 nm. Fluorescence spectra of the mixed solution with 1-butanol and n-hexane were measured, and the fluorescence intensity shows a linear relationship with the volume ratio of the former. For the mixed solution of 1-butanol and alcohol, the authors found that at different wavelength, as the matching of 1-butanol and alcohol solution changes, the law for the intensity of fluorescence also changes. Meanwhile, the mathematical formula for the fluorescence position of the mixed solution was listed, and the error between calculation and experiment has been proved to be small. This may provide some reference for the further research of fluorescence spectrum of alcohol resolutions.

[Study on three-dimensional fluorescence spectra of Yanghe classical distilled spirits].

In the present paper, the liquors of Hai zhi lan, Tian zhi lan and Meng zhi lan were selected as the objects, and by using equipment of UV-240 ultra-violet spectrophotometer and Sp-2558 multifunctional spectrometer, their absorption and three-dimensional fluorescence spectra induced by UV light were studied respectively. The maximum absorption wavelengths for all of them were located at 212 and 275 nm, but each has different intensity at 212 nm. Moreover, their three-dimensional fluorescence spectra were detected when they were induced by suitable UV-light, The results show that each of the spirits can emit three strong fluorescence lines at 310, 420 and 610 nm respectively when excited by UV-light at 245 nm. Furthermore, we found each of them can emit another two strong fluorescence lines when they absorb the UV-light at 310 and 345 nm. The authors found that they all have five different fluorescence peaks, but each has different intensity. According to the experimental phenomenon, through a careful analysis, it is pointed out that the differences of the five fluorescence peaks basically reflect the aging process and different content of the liquor. The three different brand yanghe classical liquors were identified fast and accurately. The paper also offered a kind of way to determine the quality and brand of white spirit.

[Study on fluorescence spectra of Chinese rice wine].

Chinese rice wine has a history of more than 5000 years, only in China, hich is called "Nation Wine", and Shao Xing Chinese rice wine is a representative of it. The fluorescence spectra of 3 kinds of Shao Xing Chinese rice wine with different storage age induced by suitable UV-light were obtained in the present paper through experiment. The authors compared and analyzed them comprehensively by using three dimensional contour and two dimensional fluorescence technique, and found that their best induced light was all in the vicinity of 370 nm. The peak wavelength of 3 year storage age wine was 504 nm, while 488 nm and 505 nm were for 5 and 8 year storage age wine respectively. The emitted fluorescence existed in 400 to 680 nm, which had wide peak. More over, the emitting mechanism of Shao Xing Chinese rice wine was discussed. The authors also have explained the similarity and difference of fluorescence spectra among the 3 kinds of wine. The reason for wide fluorescence peak was also analyzed. This investigation contributes to the study of the characteristic, year detection and food safety of Chinese rice wine.