title: 3-Aminophenylboronic acid-functionalized CuInS2 quantum dots as a near-infrared fluorescence probe for the detection of dicyandiamide.
abstract: In this paper, a simple and highly selective method for the determination of dicyandiamide (DCD) was developed based on the fluorescence quenching of functionalized CuInS2 quantum dots (QDs). Water-soluble CuInS2 QDs, capped by mercaptopropionic acid, were directly synthesized in aqueous solution and then covalently linked to 3-aminophenylboronic acid molecules to form the 3-aminophenylboronic acid-functionalized CuInS2 QDs (F-CuInS2 QDs) that had a fairly symmetric fluorescence emission centered at 736 nm. Based on the cyclization of the guanidine group of DCD with 2,3-butanedione and 3-aminophenylboronic acid, the fluorescence of the F-CuInS2 QDs is quenched by DCD in the presence of 2,3-butanedione. This method effectively distinguishes DCD from other amino acids and nitrogen pollutants, such as melamine, in real milk samples. Under optimum conditions, there was a good linear relationship between the fluorescence intensity of F-CuInS2 QDs and the concentration of DCD in the range of 2.0 × 10(-6) to 2.0 × 10(-3) mol L(-1), with a detection limit of 0.6 μmol L(-1).
authors.affiliation: College of Life and Health Sciences, Northeastern University, Shenyang 110000, China.
authors.forename: Siyu
authors.initials: S
authors.lastname: Liu
authors.forename: Shu
authors.initials: S
authors.lastname: Pang
authors.forename: Hui
authors.initials: H
authors.lastname: Huang
authors.forename: Xingguang
authors.initials: X
authors.lastname: Su
mesh_terms: D001897:Boronic Acids / Q000737:chemistry*; D005456:Fluorescent Dyes / Q000737:chemistry*; D006146:Guanidines / Q000032:analysis*; D006863:Hydrogen-Ion Concentration; D045663:Quantum Dots; D013050:Spectrometry, Fluorescence; D013696:Temperature
chemical_list: D001897:Boronic Acids; D005456:Fluorescent Dyes; D006146:Guanidines; C028592:3-aminobenzeneboronic acid; C004711:dicyandiamido