The Synthesis Of Ag Nanoclusters And Its Application As Fluorescent And Colorimetric Sensor In Detection

Abstract:Metal nanoclusters have aroused a great deal of interest due to their molecule-like behavior, unique optical properties and favorable biocompatibility. Among metal nanoclusters, fluorescent Ag nanoclusters (Ag NCs) are proved to be the attractive versatile sensors, owing to its strong fluorescence behaviors and highly sensitive to the surrounding environments. To date, there have been plenty of reports about the applications of Ag NCs as fluorescent or colorimetric sensors, especially in the detection of heavy metal ions (HMI) and glucose.However, most of the reported sensors are restricted in the detection of a certain material or one type of analytes. The researches about multiple-alternative detection of different kinds of materials and at the same time with no interfere with each other are rarely be mentioned. In the view of material utilization and detection cost, this single detection scheme will undoubtedly great limit their further applications in the actual detection. As we all know, the pollution caused by heavy metal ions and the large population affected by diabetes have always been the serious and urgent social problems. Therefore, the development of the multifunctional materials which can be used to sensing both the heavy metal ions and glucose are of great importance.In this article, we present a new and easy approach to synthesize fluorescent PMAA-Ag NCs via the hydrothermal method in the presence of poly(methacrylic acid sodium salt)(PMAA) and the PMAA/PVP-Ag NCs in the presence of PMAA and poly (vinyl pyrrolidone)(PVP). We demonstrate that the PMAA-Ag NCs are sensitive to both mercury and copper ions based on a fluorescence quenching effect. Excellent linear relationships existed between the quenching degree of Ag NCs and the concentrations of Hg2+or Cu2+ions in the range of10nM to20μM or10nM to30μM, respectively. In addition, Cu2+can be successfully masked by the addition of detection of Hg2+or repeated detecting of Cu2+. The fluorescent quenching mechanisms of Hg2+and Cu2+detection by the Ag NCs were also investigated and discussed by using the TEM and UV measurements.We also found the multifunctional use of PMAA/PVP-Ag NCs in selective sensing Hg2+, and colorimetric detection of glucose. The Ag NCs were used in the sensitive and selective detection of Hg2+based on the fluorescence turn-off behavior. The detection limit was10nM in the linear range from10nM to16μM. We further demonstrate the novel use of the as-prepared Ag NCs as a dual channel probe for fluorescence turn-on and colorimetric detection of glucose with a pretty low detection limit of50μM.