The Establishment And Application Of Silver Nanoclusters Based On Anionic Dye

Silver nanoclusters (Ag NCs) continued to hold an important position in analytical chemistry. Ag NCs as a new kind of fluorophores had attracted special attention due to their interesting size-dependent electrical structure, optical, physical and chemical properties. They had been used in the field of biological imaging, analysis, catalysis, medicine, electronics and environmental monitoring. Owing to a strong tendency to aggregate of sliver atoms in water, it was necessary to prevent Ag NCs from its agglomeration to obtain stable strong fluorescent Ag NCs. Up to now, many significant efforts had been devoted to the synthesis and application of Ag NCs. Variety of ligands/templates were used to synthesize Ag NCs as stabilizing agents. In this paper, we firstly bulit the synthesis method of Ag NCs utilized anionic dyes as stabilizer. Novel fluorescent Ag NCs with different sizes were synthesized based on two kinds of anionic dyes (amido black 10B, bromocresol green), and they had been further used to develop two kinds of fluorescent probes. Meanwhile, a visual method for Ag+ analysis was built based on the characteristic absorption peak of amido black 10B changed linearly with the difference in concentration of Ag+. The main research content is as follows:(1) An novel fluorescent Ag NCs was synthesized using amido black 10B (AB) as stabilizing agent, and then employed for detection of copper ion (Cu2+). The AB-stabilized Ag NCs (AB-Ag NCs) were well dispersed in aqueous solution with an average diameter around 1.3 nm and exhibited illustrious blue fluorescence emission. Moreover, the fluorescence of AB-Ag NCs could be quenched efficiently by Cu2+, which might be resulted from the coordination between Cu2+ and the free recognition group of AB on surfaces of AB-Ag NCs, inducing the aggregation of AB-Ag NCs. Based on the linear decrease of fluorescence intensity, the Cu2+ concentration was determined in the range of 0.01-1.1 ?mol·L-1, and the detection limit (LOD) was 4.0 nM. Based on the above method, the developed AB-Ag NCs probe was successfully further applied to detect Cu2+ in three electroplating effluents, which showed high accuracy.(2) Based on the reduction of amido black 10B by sodium borohydride (NaBH4) could be efficiently catalyzed by low concentration of Ag+, which was used to detect Ag+ with UV-visible spectrophotometer. In the optimal detection condition, we found that the change of absorption value (AA) at 616 nm was proportional to the logarithm of the concentrations of Ag+ in the range of 0.005 to 0.5?M, and the color of the solution presented gradient change along with the concentration of Ag+. According to this, we developed a sensitive colorimetric for trace Ag+ detection. This method could recognize trace Ag+ of mixed solution, with low detection limit, high sensitivity, good selectivity and visualization etc.(3) A new fluorescent probe for cattle albumin (BSA) was built based on a novel BCG-Ag NCs which were synthesized using bromocresol green (BCG-Ag NCs). The BCG-Ag NCs exhibited good water-soluble property and fluorescence emission property. Under appropriate conditions, BSA could combine with BCG-Ag NCs through electrostatic binding, which made its size become bigger and decreased the fluorescence. The concentration of BSA and negative logarithm of the fluorescence intensity value showed good linear relationship in the range of 0.1 mg·L-1-0.001 mg·L-1. Thus, a simple, low-cost method for BSA detection was established.