Gold nanoparticles (AuNPs) were deposited on a glassy carbon(GC) substrate by constant potential
electrolysis and characterized by cyclic voltammetry in H2SO4 and field emission gun scanning electron
microscopy(FEG-SEM).
Themodified AuNPs–GC electrode was used for low Hg(II) concentration
detection using a Square Wave Anodic Stripping Voltammetry (SWASV) procedure which included a
chloride desorption step.
The comparison of the obtained results with our previous work in which no
desorption step was used showed that this latter step significantly improved the analytical performances,
providing a three time higher sensitivity and a limit of detection of 80 pM for 300 s preconcentration, as
well as a lower average standard deviation.The influence of chloride concentration on theAuNPs–GC
electrode response to Hg(II)trace amounts was also studied and its optimal value confirmed to be in the
102 M range. Finally,the AuNPs–GC electrode was used for the determination of Hg(II) inanatural
groundwater sample from south of France. By using a preconcentration time of 3000 s, a Hg(II) con-
centration of1973 pM was found,which compared well with the result obtained by cold vaporatomic
fluorescence spectroscopy(2272 pM).
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