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

• Simple and elegant potentiostatic method is described for synthesis of silver nanoclusters.
• Micellar stabilized silver nanoclusters have been extensively characterized.
• Designed square wave voltammetry based nitrate sensor.
• The sensitivity and limit of detection are several orders lower compared to hitherto reported sensors.

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 × 10−15 mol dm−3 and wide linear response range from 1 × 10−14 to 1 × 10−7 mol dm−3 with R2 value of 0.9936 for nitrate. The sensor shows a good precision of 1.2% (n = 3) at 10−12 mol 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.

Figure optionsDownload as PowerPoint slide