Influence of the gold nanoparticles electrodeposition method on Hg(II) trace electrochemical detection

Abstract

Gold nanoparticles (AuNPs) were deposited on Glassy Carbon (GC) substrate by using three electrochemical techniques: Cyclic Voltammetry (CV), Chronoamperometry (CA) and Potentiostatic Double-Pulse (PDP). For each electrodeposition method, the resulting AuNPs-modified electrodes were characterized by CV in H 2 SO 4 and Field Emission Gun Scanning Electron Microscopy (FEG-SEM). CA was found to be the best electrodeposition mode for controlling the morphology and the density of AuNPs. The modified electrodes were used for low Hg(II) concentration detection using Square Wave Anodic Stripping Voltammetry (SWASV). AuNPs obtained by CA afforded the best amperometric response while involving the lowest amount of charge during the electrodeposition step (Q Au(III)). This analytical response is correlated to both the smallest particle size (ca. 17 nm in diameter) and the highest particle density (332 particles m −2), thus displaying high electrode effective surface area. In these optimal conditions, using a Hg(II) preconcentration time of 300 s, the nanosensor array exhibited a linearity range from 0.80 to 9.9 nM with a sensitivity of 1.16 A nM −1. A detection limit of 0.40 nM (s/n = 3) was reached.

Impedimetric and stripping voltammetric determination of methamphetamine at gold nanoparticles-multiwalled carbon nanotubes modified screen printed electrode

“…The cyclic voltammogram shows no reduction peak in the reverse scan, indicating an irreversible reaction for MA oxidation. [45,46], for the proposed electrode peak current of MA oxidation in NaOH solution was much higher than in acidic one. It can be explained by this fact that the MA secondary amine group is more easily oxidized in basic solution than in acidic solution, and this data correlates well with the pK a = 10.1 of the amine function of MA [14].…”

Mercury(II) trace detection by a gold nanoparticle-modified glassy carbon electrode using square-wave anodic stripping voltammetry including a chloride desorption step

“…Natural water dedicated to Hg(II) trace detection was sampled from Font Estramar (42° 51′ 31.73″ N 2° 57′ 30.776″ E), which is a submarine groundwater discharge located at Salses-le- HAuCl 4 by potentiostatic electrolysis at 0 V for 15 s, according to our previous work [49].…”

“…Recently, we reported on an AuNPs-modified glassy carbon (AuNPs-GC) sensor dedicated to Hg(II) trace 4 determination [48,49]. The amperometric response towards Hg(II) was found to be dependent on AuNPs size and density [49] and was hampered by a broad baseline due to chloride anions contribution. We proved that this was rather due to Cl -adsorption onto the Au surface than to calomel formation [50], contrary to what has been reported previously in the literature [51].…”

“…AuNPs may be prepared either by chemical [44] or electrochemical route [42,43,45]. Recently, we reported on an AuNPs-modified glassy carbon (AuNPs-GC) sensor dedicated to Hg(II) trace 4 determination [48,49]. The amperometric response towards Hg(II) was found to be dependent on AuNPs size and density [49] and was hampered by a broad baseline due to chloride anions contribution.…”

One-pot organometallic synthesis of well-controlled gold nanoparticles by gas reduction of Au(I) precursor: a spectroscopic NMR study

“…The development of simple methods to obtain AuNPs which are able to form thin films on substrates is therefore of great interest. Recently, different electrochemical methods were investigated for the deposition of AuNPs on glassy carbon electrodes for Hg(II) trace detection in water [20,21]. Despite good performance with a detection limit of 0.40 nmol of Hg.L −1 , no control of shape and dispersisty of AuNPs smaller than 15 nm were obtained by electrodeposition of HAuCl 4 in sodium nitrate electrolyte.…”