title: Surface-modified CdS quantum dots as luminescent probes for sulfadiazine determination.
abstract: A novel, sensitive and convenient determine technology based on the quenching of the fluorescence intensity of functionalized CdS quantum dots by sulfadiazine was proposed. Luminescent CdS semiconductor quantum dots (QDs) modified by thioglycollic acid (TGA) were synthesized with the microwave method. The modified CdS QDs are water-soluble, stable and highly luminescent. The possible mechanism for the reaction was also discussed. When sulfadiazine was added into the CdS QDs colloid solution, the surface of CdS QDs generates the electrostatic interaction in aqueous medium, which induces the quenching of fluorescence emission at 489 nm. Under optimum condition, the fluorescence intensity versus sulfadiazine concentration gave a linear response according Stern-Volmer equation with an excellent 0.9981 correlation coefficient. The linearity range of the calibration curve was 1.2 x 10(-5) to 2.13 x 10(-3) mol L(-1). The limit of detection (3delta) is 8.0 micromol L(-1). The relative standard deviation for five determinations of 0.13 x 10(-3)mol L(-1) sulfadiazine is 1.4%. The concentrations of sulfadiazine injections were determined by the proposed method with a satisfactory result.
authors.affiliation: Department of Analytical Chemistry, China Pharmaceutical University, Nanjing 210009, China.
authors.forename: Mingming
authors.initials: M
authors.lastname: Liu
authors.forename: Li
authors.initials: L
authors.lastname: Xu
authors.forename: Weiqing
authors.initials: W
authors.lastname: Cheng
authors.forename: Yu
authors.initials: Y
authors.lastname: Zeng
authors.forename: Zhengyu
authors.initials: Z
authors.lastname: Yan
mesh_terms: D019187:Cadmium Compounds / Q000737:chemistry*; D002138:Calibration; D005456:Fluorescent Dyes / Q000032:analysis* / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D046529:Microscopy, Electron, Transmission; D009994:Osmolar Concentration; D045663:Quantum Dots; D012680:Sensitivity and Specificity; D012995:Solubility; D013411:Sulfadiazine / Q000032:analysis* / Q000737:chemistry*; D013440:Sulfides / Q000737:chemistry*; D013499:Surface Properties; D013864:Thioglycolates / Q000737:chemistry; D014867:Water / Q000737:chemistry
chemical_list: D019187:Cadmium Compounds; D005456:Fluorescent Dyes; D013440:Sulfides; D013864:Thioglycolates; C034939:cadmium sulfide; D014867:Water; D013411:Sulfadiazine