Synthesis of silver nanoclusters, characterization and application to trace level sensing of nitrate in aqueous media

We report here the synthesis of surfactant stabilized silver nanoclusters onto a silver disc electrode by simple potentiostatic method. Characterization of silver nanoclusters by spectral (UV-vis, fluorescence, matrix-assisted laser desorption ionization time-of-flight mass spectroscopy (MALDI-TOF-MS), energy dispersive X-ray spectroscopy (EDX)), morphological (transmission electron microscopy (TEM)) and electrochemical techniques is described. The silver nanocluster modified electrode is used for square wave voltammetric sensing of traces of nitrate. The results of electroanalytical experiments reveal that the designed sensor has a very low detection limit of 1.5 X 10(-15) mol dm(-3) and wide linear response range from 1 x 10(-14) to 1 X 10(-7) mol dm(-3) with R-2 value of 0.9936 for nitrate. The sensor shows a good precision of 1.2% (n =3) at 10(-12) MOI dm(-3) of nitrate. Electrocatalytic studies undertaken with AgNC modified electrode in 0.1 mol dm(-3) NaH2PO4 buffer solution (pH 4.5) containing 10(-8) mol dm(-3) NO3- by scan rate variation and single step chronoamperometric studies. (c) 2013 Elsevier Ltd. All rights reserved.