title: Determination of L-tyrosine by beta-cyclodextrin sensitized fluorescence quenching method.
abstract: A novel beta-cyclodextrin (beta-CD) sensitized fluorescence quenching method for the determination of l-tyrosine (l-Tyr) with Mo(VI)-phenyl-fluorone (PF) as a fluorescence probe has been developed. The fluorescence intensity of Mo(VI)-PF-beta-CD was diminished as the l-tyrosine was added, the fluorescence quenching value DeltaF=F(beta-CD-Mo-PF)-F(beta-CD-Mo-PF-l-Tyr) was enhanced in beta-CD and there was a linear relationship between the DeltaF and the concentration of l-Tyr. Under the optimal conditions, the linear range of calibration curve for the determination of l-tyrosine was 0.3-20.0microgmL(-1); the detection limit was 0.094microgmL(-1). NaOH (10%, w/v) is the best reagent of hydrolysis in sample preparation. The sensitized mechanism of beta-cyclodextrin was discussed. The method has been applied to the determination of l-tyrosine in spirulina and food samples with satisfactory results.
authors.affiliation: Department of Chemistry, Yangzhou University, Yangzhou, Jiangsu 225002, People's Republic of China. xszhu@yzu.edu.cn
authors.forename: Xiashi
authors.initials: X
authors.lastname: Zhu
authors.forename: Suqin
authors.initials: S
authors.lastname: Xu
mesh_terms: D000596:Amino Acids / Q000494:pharmacology; D002138:Calibration; D056831:Coordination Complexes / Q000032:analysis; D005456:Fluorescent Dyes; D005504:Food Analysis / Q000379:methods*; D006863:Hydrogen-Ion Concentration; D057230:Limit of Detection; D011188:Potassium / Q000494:pharmacology; D012680:Sensitivity and Specificity; D013050:Spectrometry, Fluorescence / Q000379:methods*; D053545:Spirulina / Q000737:chemistry; D013431:Sulfates / Q000494:pharmacology; D013696:Temperature; D013997:Time Factors; D014443:Tyrosine / Q000032:analysis*; D047392:beta-Cyclodextrins / Q000737:chemistry / Q000494:pharmacology*
chemical_list: D000596:Amino Acids; D056831:Coordination Complexes; D005456:Fluorescent Dyes; D013431:Sulfates; D047392:beta-Cyclodextrins; D014443:Tyrosine; C031215:betadex; D011188:Potassium