title: Phosphorescence detection of L-ascorbic acid with surface-attached N-acetyl-L-cysteine and L-cysteine Mn doped ZnS quantum dots.
abstract: N-Acetyl-L-cysteine (NAC) and L-cysteine (Cys) capped Mn doped ZnS quantum dots (NAC-Mn/ZnS QDs and Cys-Mn/ZnS QDs) are firstly prepared by hydrothermal methods. These QDs display strong phosphorescence emission peaks at 583 and 580 nm upon excitation at 315 and 306 nm, respectively. Since their room-temperature phosphorescence is efficiently quenched by L-ascorbic acid (AA), they have been employed as phosphorescence probes for detecting AA. The linear working ranges are 2.5-37.5 and 2.5-47.5 µM and the limits of detection are 0.72 and 1.38 µM for NAC-Mn/ZnS QDs and Cys-Mn/ZnS QDs, respectively. The possible quenching mechanisms have been discussed in detail. The QDs probes are highly selective to AA over other common ions, amino acids, glucose and bovine serum album. Finally, they have been applied successfully for detection of AA in human urine samples with satisfactory results. The recoveries are 98-104%. Our work provides a simple and convenient phosphorescence method to determine AA in real samples.
authors.affiliation: School of Chemistry and Chemical Engineering, Shanxi University, Taiyuan 030006, PR China; School of Basic Medical Science, Shanxi Medical University, Taiyuan 030001, PR China.
authors.forename: Wei
authors.initials: W
authors.lastname: Bian
authors.forename: Jing
authors.initials: J
authors.lastname: Ma
authors.forename: Wenrong
authors.initials: W
authors.lastname: Guo
authors.forename: Dongtao
authors.initials: D
authors.lastname: Lu
authors.forename: Meng
authors.initials: M
authors.lastname: Fan
authors.forename: Yanli
authors.initials: Y
authors.lastname: Wei
authors.forename: Yingfu
authors.initials: Y
authors.lastname: Li
authors.forename: Shaomin
authors.initials: S
authors.lastname: Shuang
authors.forename: Martin M F
authors.initials: MM
authors.lastname: Choi
mesh_terms: D000111:Acetylcysteine / Q000737:chemistry*; D001205:Ascorbic Acid / Q000652:urine*; D003545:Cysteine / Q000737:chemistry*; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D057230:Limit of Detection; D008163:Luminescent Measurements; D008345:Manganese / Q000737:chemistry; D015335:Molecular Probes / Q000737:chemistry*; D045663:Quantum Dots / Q000737:chemistry*; D013440:Sulfides / Q000737:chemistry; D013696:Temperature; D017967:Zinc Compounds / Q000737:chemistry
chemical_list: D015335:Molecular Probes; D013440:Sulfides; D017967:Zinc Compounds; D008345:Manganese; D003545:Cysteine; C031238:zinc sulfide; D001205:Ascorbic Acid; D000111:Acetylcysteine
keywords: L-Ascorbic acid; Mn doped ZnS quantum dots; Phosphorescence probe