Determination of ppt Level Chromium(VI) Using the Gold Nano-Flakes Electrodeposited on Platinum Rotating Disk Electrode and Modified with 4-Thiopyridinium

Abstract

The nano-gold layer formed on the platinum rotating disk electrode (nano-Au/Pt-RD) inherited the catalytic property for Cr(VI) reduction from platinum surface and owned the good features of nano-gold such as insensitivity with hydrogen ion, high surface area, augmenting diffusion of Cr(VI) and ability for self-assembling with 4-pyridine-ethanethiol (PET) through Au←S linkages, to form PET/nano-Au/Pt-RD electrode capable of accumulating Cr(VI) from sample. The obtained PET/ nano-Au/Pt-RD electrode showed an extreme sensitivity to Cr(VI). By using this electrode, 1.09 ng•L −1 was the detection limit of differential pulse adsorptive cathodic stripping voltammetry for Cr(VI) with the accumulation time of only 2 min. Moreover, this electrode was reproducible with 3.5% RSD for 30 times of Cr(VI) accumulating and stripping. In addition, this electrode was also selective for Cr(VI) determination, which was not almost interfered by other inorganic ions.

Amperometric detection of carbohydrates based on the glassy carbon electrode modified with gold nano-flake layer

“…In our previous study [11], the electro-deposition of gold nano-flakes (nano-Au) on electrode surface of RD electrode from HAuCl 4 solution depends on the activity of electrode surface for the reduction of HAuCl 4 into nano-Au, the transferring rate of HAuCl 4 to electrode surface and the deposition time (t P ). The activity of electrode surface is conducted by the deposition potential (E P ).…”

“…Following the procedures from previous studies [9][10][11][12][13], the Au-RD working electrode was polished with the water slurry of 0.05 lm alumina particles. The residual polishing material was removed using ethanol and then water in an ultrasonic bath.…”

“…The transferring rate of HAuCl 4 is proportional to the HAuCl 4 concentration (C Au(III) ) and flow rate of HAuCl 4 solution (v F ). When optimizing electro-deposition of gold nano-flakes (nano-Au) on electrode surface of the electrochemical cell of HPLC system, we kept the activity of electrode surface at the optimal E P of À200 mV according to our previous study [11] and investigated the transferring rate of HAuCl 4 to electrode surface by changing C Au(III) while constant v F of 0.5 mL because C Au(III) affected directly to the size of nano-Au [12]. The optimal C Au(III) is able enough to show the optimal ratio between the reduction rate of Au(III) on electrode surface and the transferring rate of HAuCl 4 to electrode surface.…”

Recent Advances in Electrochemical Monitoring of Chromium

“…The prepared sensor was utilized for the determination of Cr(VI) in contaminated groundwater with an average recovery of 96%. Moreover, Huy Du Nguyen et al [ 52 ] reported a new voltametric sensor built on the modification of a platinum rotating disk electrode by gold nano-flakes and 4-pyridine-ethanethiol through electrodeposition approach. The developed sensor showed excellent properties for Cr(VI) sensing in Coastal water with enhanced sensitivity and reproducibility and a very low detection limit (0.001 µg·L −1 ).…”

Citrate-Capped Gold Nanoparticle as a Ligand for Chromium(III) Ion: Optimization and Its Application in Contaminated Tap Water

“…Exposure to Cr can produce different point mutations in DNA, chromosomal damage, and oxidative alterations in proteins in addition to adduct formation. Because each form of Cr has a different level of toxicity, the health impacts of each are varied [1][2][3].…”