Abstract:
Gold atomic cluster based nanocomposites are important in the field of energy and sensing applications due to their interesting optical, electronic, chemical and catalytic properties. In the present study a chitosan stabilized gold atomic cluster nanocomposite was synthesised by a simple electrochemical technique based on the anodic dissolution of a gold electrode in the presence of a cationic surfactant, cetyl trimethyl ammonium bromide (CTAB), and a biopolymer, chitosan, on a gold electrode. The gold clusters formed were characterized by DLS, TEM, MALDI-TOF-MS, XPS, fluorescence and cyclic voltammetry. The developed gold atomic cluster-chitosan (AuAC-Chit) nanocomposite modified gold electrode was highly sensitive and selective for the electrochemical detection of Hg(II) ions. It offers a wider calibration range of 10(-14)-10(-7) M with a limit of detection (LOD) of 0.8 x 10(-14) M and a limit of quantification (LOQ) of 6.6 x 10(-14) M, much below the guideline value of 1 x 10(-8) M stipulated by United States Environmental Protection Agency (USEPA), accompanied by a good precision of 1.06% for 10(-13) M of Hg(II). The designed sensor is selective to Hg(II) ions in the presence of other coexisting species.
