Simultaneous Electrochemical Detection of Co(II) and Cu(II) by 1‐Diazo‐2‐Naphthol‐4‐Sulfonic Acid/MWCNTs Modified Electrode

Abstract

This work describes a simple preparation of 1‐diazo‐2‐naphthol‐4‐sulfonic acid (1,2,4‐acid) and multiwalled carbon nanotubes (MWCNTs) modified glassy carbon electrode (GCE) for the simultaneous detection of Co(II) and Cu(II). MWCNTs, with their good conductivity and large surface area, were drop‐casted onto the surface of the GCE prior to the electrodeposition of 1,2,4‐acid, a metal chelating agent. Co(II) and Cu(II) were simultaneously measured by differential pulse anodic stripping voltammetry (DPASV) in a batch system. Under optimum conditions, the linear range of Co(II) was between 0.10 and 2.5 μg mL−1 with an LOD of 80 ng mL−1. Two linear ranges were obtained for Cu(II), 0.0050 to 0.030 μg mL−1 and 0.040 to 0.25 μg mL−1,with an LOD of 2.4 ng mL−1. The method offered a high operational stability for up to 52 measurements (RSD=3.4 % for Co(II) and 2.6 % for Cu(II)) and good reproducibility (RSD=1.2 % for Co(II) and 1.7 % for Cu(II)). In the simultaneous detection of Co(II) and Cu(II), there was no effect from common interferences found in wastewater. The method was successfully applied in real water samples with good recoveries (88.2±0.8 to 102.0±0.8 % for Co(II) and 96.5±0.4 to 103.8±0.9 % for Cu(II)) and the results were in good agreement with those obtained from inductively coupled plasma optical emission spectrometry (ICP‐OES) (P>0.05).

The synthesis of nitrogen and sulfur co-doped graphene quantum dots for fluorescence detection of cobalt(ii) ions in water

“…Up to the present time, many analysis methods have been developed to detect cobalt ions, for example, electrochemical methods, 36,37 inductively coupled plasma optical emission spectrometry (ICP-OES), 38 and colorimetric methods. 32,[39][40][41] Among these techniques, fluorometry has attracted much interest for metal sensing owing to its simplicity, high sensitivity, rapid response, low-cost detection, and convenience.…”

An Electrochemical Sensor for the Detection of Cu2+ Based on Gold Nanoflowers‐modifed Electrode and DNAzyme Functionalized Au@MIL‐101 (Fe)

“…As can be seen from the calibration plot ( Figure 9B), there was a good linear relationship between the peak current and the logarithm of the Cu 2 + concentration in the range of 0.001 to 100 μM (I = 0.3404lnC Cu2 + + 2.6177, R 2 = 0.998), with a low detection limit of 0.457 nM (3δ). Compared with previous reports, this electrochemical sensor had a comparable low detection limit and wide linear range (Table S1) [6][7][8][9][10][38][39][40]. According to the U.S. Environmental Protection Agency (EPA), the maximum allowable concentration of copper ion in drinking water is 20 μM.…”

Evaluation of voltammetric method for the determination of electrodeposited copper in citrate medium validated by ICP-OES

“…Electroanalytical technique validations using ICP-OES and ICP-MS are limited in the literature. A few researchers [18][19][20], have used redissolved solution voltammetry to preconcentrate various metals, in order to provide low limits of detection and quantification. Oliveira et al [18] developed a biochar-modified carbon paste electrode for use with differential pulse adsorptive stripping voltammetry (DPAdSV) for the determination of copper (II) ions in distillate samples (cachaça, vodka, gin, and tequila).…”

“…Zamhari et al [20] reported the simultaneous electrochemical detection of Co(II) and Cu(II) by 1diazo-2-naphthol-4-sulfonic acid/MWCNTs modified glassy carbon electrode (GCE) by differential pulse anodic stripping voltammetry (DPASV) in a batch system. The method was successfully applied in real water samples and the results were in good agreement with those obtained by ICP-OES.…”