Simultaneous Adsorptive Stripping Voltammetric Analysis of Heavy Metals at Graphenated Cupferron Pencil Rods

Abstract

Electroanalysis of heavy metal ions in the presence of cupferron ligands has been extensively studied due to its ability to form stable metallic coordination complexes. Herein, electrochemically reduced graphene oxide (ERGO) sheets were for the first time employed in conjunction with low-cost, disposable pencil graphite rods and in-situ plated thin mercury films (HgF) for the simultaneous detection of Cd2+, Cu2+, Pb2+, and Zn2+ in the presence of cupferron as a chelating agent by square-wave adsorptive cathodic stripping voltammetry (SW-AdCSV). The technique is based on the catalytic reduction of adsorbed cupferron-metal ion complexes at the surface of the ERGO-HgF-PGE at 0.1 V for 60 s in 0.1 M acetate buffer solution (pH 4.6). Owing to the improved electronic and surface effects associated with ERGO inclusion, improved sensitivity was further achieved. Under optimized conditions, the ERGO-HgF-PGE showed a linear relationship from 20 to 200 µg.L-1 with detection limits below the US-EPA of 0.17 μg.L-1 , 0.02 μg.L-1 , 0.17 μg.L-1 and 0.14 μg.L-1 for Cd2+, Cu2+, Pb2+ and Zn2+, respectively at a deposition time of 60 s. The ERGO-HgF-PGE exhibited highly reproducible results with negligible intermetallic interferences and applied successfully to the determination of trace metals in tap water with satisfactory results.

Determination of Paracetamol on Electrochemically Reduced Graphene Oxide–Antimony Nanocomposite Modified Pencil Graphite Electrode Using Adsorptive Stripping Differential Pulse Voltammetry

“…Furthermore, Da Silva et al [ 24 ] evaluated SbNPs/rGO and CuNPs/rGO composites on GCE surfaces for the oxidation of levofloxacin using DPV, and the LODs were found to be 4.1 × 10 −8 mol·L −1 and 1.7 × 10 −8 mol·L −1 , respectively [ 24 ]. Our research group previously fabricated a sensor based on electrochemically reduced graphene oxide modified on an in situ plated bismuth pencil graphite electrode [ 25 ] and, recently, an in situ plated thin mercury film modification [ 26 ] was achieved for the detection of trace metals in water. In this paper, a GO-Sb dispersion was electrochemically deposited onto a pencil graphite electrode following an electrochemical reduction step to develop an electrochemically reduced graphene oxide–antimony nanocomposite modified pencil graphite electrode (ERGO-SbNPs-PGE).…”

Chronocoulometric Quantum Dot Aptasensor for SARS‐CoV‐2 Nucleocapsid Protein Biomarker

“…The linear dependence of peak current with scan rate indicates that the redox peak currents are driven by adsorption‐controlled processes at the electrode surface, which is confirmed by the non‐linearity of the square root of the scan rate versus the peak current [43,44] . The ECSA was calculated by using the Randles‐Sevcik equation [45,46] $$$\vcenter{\openup.5em\halign{$\displaystyle{#}$\cr {I}_{p}=2.69\times {10}^{5}\ A{D}^{1/2}{n}^{3/2}{v}^{1/2}C\hfill\cr}}$$$ …”

Electrochemical stripping analysis

“…Other fields where ESA is invaluable are forensic analysis, for example for gunshot residue detection 161 , fuel quality control 162 , battery research and energy applications 163 and pharmaceuticals6. Notably, multi-element methods can quantify several target metals at the same working electrode in a single run 45,164 , or at devices with spatially separated working electrodes with each electrode dedicated to a single target metal 165 . An example of multi-element ASV analysis in a single run is illustrated in Fig.…”