FLUORESCENT CHARACTERISTIC OF ρ-COUMARIC ACID,CAFFENIC ACID AND CHLOROGENIC ACID

MI Pei-pei1,ZHANG Li-xia1*,WANG Ri-wei2,QIU Xu-dong2,YANG Qi1(1.College of Horticulture Science and Engineering,Shandong Agricultural University,Taian 271018,China;2.College ofChemistry And Material Science,Shandong Agricultural University,Taian 271018,China)

ρ-coumaric acid;caffeic acid;chlorogenic acid;fluorescence;influencefactors

The effects of the pH,solvents,concentration on the fluorescent characteristic of the ρ-coumaric acid,caffenic acid and chlorogenic acid were studied.The results showed that the factors which affected the fluorescent spectra ofthe three phenolic acidswere pH value and solvents.The maximum excitation and emission wavelength of the three phenolic acidsmovedto the long wavelength with the enthance of alkalinity.There had obvious effects of hydrogen bonds between the three phenolic acidsand solvents(water,methanol,dimethyl sulfoxide).Whenρ-coumaric acid,caffenic acid and chlorogenic acid was dissolved in methanol,respectively their Stoke's shift value became smaller than one in water.The main influence factors of the fluorescent intensity were pH and concentration.It reached the maximum intensity when pH of solvent was 10 or the concentration of aqueousρ-coumaric acid(λex/λem=350/440 nm) was 10 mg/L,and pH of solvent was 8.5 or the concentration of aqueous caffenic acid(λex/λem=385/465 nm) was 300 mg/L,and pH of solvent was 11.5 or the concentration of aqueous chlorogenic acid(λex/λem=380/490 nm) was 90 mg/L.