Study On The New Methods For Sunset Yellow, Zinc And Lipoic Acid Determination By Spectrofluorimetry

Fluorescence spectroscopy analysis is high sensitivity, selectivity, and with less sample easy to use, etc., which can be widely used in food, medicine, and environmental testing and many other areas. This paper should focus on the interactions between acriflavine（AF）- sunset yellow（SY）, zinc ion- phenanthroline（phen） and fluorescent Carbon Dots（CDs）- lipoic acid（LA） by using fluorescence spectroscopy, thus accordingly established a new method for detecting sunset yellow, zinc and lipoic acid. The research contents are outlined as follows:1. Determination of sunset yellow based on the fluorescence quenching of acridine flavinIn pH 5.0 of Britton-Robinson（BR） buffer solution, adding sunset yellow can make fluorescence intensity of acridine flavin decreased. A good linear relationship was obtained from 2.0 × 10-6 to 2.0 × 10-5 mol·L-1, the detection limit was 2.95 nmol·L-1, The optimum conditions and influencing factors of fluorescence quenching reaction were studied in this paper. Meanwhile, the method could be used to detectionin sunset yellow in beverages.2. Determination of zinc ion by fluorescence enhancement method with phenanthroline as probeIn pH 5.8 of Britton-Robinson（BR） buffer solution, highly sensitive response was found in the fluorescence of phenanthroline（phen） toward Zn²⁺. The maximum excitation wavelength and maximum emission wavelengths were located at 302 nm and 362 nm, respectively. The fluorescence enhancement values（ΔF） of phen showed good linear relationship to the concentration of Zn²⁺ in the range of 2.0 × 10-5 1.6 × 10-4 mol·L-1. the detection limit was 1.056 ×10-7 mol·L-1. The appropriate conditions and factors of the fluorescence enhancement reaction and the influence of coexisting substances on the system were discussed in this work..3. Study the interaction of Carbon Dots- lipoic acid by using fluorescence spectroscopyIn this work, a kind of high- performance fluorescent Carbon Dots were synthesized by using citric acid and ethylene diamine as carbon source. In pH 9.0 of Britton-Robinson（BR） buffer solution, when lipoic acid was added in Carbon Dots solution, the fluorescence intensity of Carbon Dots was significantly reduced at 442 nm. A good linear relationship was obtained from 5.0 × 10-6 to 4.5 × 10-5 mol·L-1, and the detection limit was 8.21 × 10-8 mol·L-1, thus established a new detection method of lipoic acid.