Assessment of Melamine in Different Water Samples with ZnO‐doped Co₃O₄Nanoparticles on a Glassy Carbon Electrode by Differential Pulse Voltammetry

Abstract

In this investigation, a melamine electrochemical sensor has been developed by using wet‐chemically synthesized low‐dimensional aggregated nanoparticles (NPs) of ZnO‐doped Co3O4 as sensing substrate that were decorated onto flat glassy carbon electrode (GCE). The characterization of NPs such as UV‐Vis, FTIR, XRD, XPS, EDS, and FESEM was done for detailed investigations in optical, functional, structural, elemental, and morphological analyses. The ZnO‐doped Co3O4 NPs decorated GCE was used as a sensing probe to analyze the target chemical melamine in a phosphate buffer at pH 5.7 by applying differential pulse voltammetry (DPV). It exhibited good performances in terms of sensor analytical parameters such as large linear dynamic range (LDR; 0.15–1.35 mM) of melamine detection, high sensitivity (80.6 μA mM−1 cm−2), low limit of detection (LOD; 0.118±0.005 mM), low limit of quantification (LOQ; 0.393 mM), and fast response time (30 s). Besides this, the good reproducibility (in several hours) and repeatability were investigated under identical conditions. Moreover, it was implemented to measure the long‐time stability, electron mobility, less charge‐transfer resistance, and analyzed diffusion‐controlled process for the oxidation reaction of the NPs assembled working GCE electrode, which showed outstanding chemical sensor performances. For validation, real environmental samples were collected from various water sources and investigated successfully with regard to the reliability of the selective melamine detection with prepared NPs coated sensor probe. Therefore, this approach might be introduced as an alternative route in the sensor technology to detect selectively unsafe chemicals by an electrochemical method with nanostructure‐doped materials for the safety of environmental, ecological, healthcare fields in a broad scale.

Sensitive Electrochemical Detection of 4-Nitrophenol with PEDOT:PSS Modified Pt NPs-Embedded PPy-CB@ZnO Nanocomposites

“…Therefore, the working electrode based on the Pt-NP-embedded PPy-CB@ZnO NCs/GCE has more electric conductivity, favorable to the electrochemical analysis of an analyte. Similar observations have been described elsewhere [ 39 , 40 ]. Stability is an important sensor criterion in the electrochemical analysis of a working electrode.…”

Efficient Detection of 2,6-Dinitrophenol with Silver Nanoparticle-Decorated Chitosan/SrSnO3 Nanocomposites by Differential Pulse Voltammetry

“…Therefore, the working electrode based on the Ag-decorated Chitosan/SrSnO 3 NC/GCE has a higher current response, favorable to the electrochemical analysis of an analyte. Similar observations have been described elsewhere [ 43 , 44 ]. To evaluate the molecular diffusion on the surface of the anticipated working electrode, a plot showing the current versus the square root of the scan rate at a range of 50~300 mV/s is shown in Figure 7 c. The experiment was conducted using 0.1 mM K 4 [Fe(CN) 6 ].…”

Oxygen Vacancy-Enriched CoFe2O4 for Electrochemically Sensitive Detection of the Breast Cancer CD44 Biomarker

“…The results demonstrate that the synthesized CoFe 2 O 4– x contains Co, Fe, O, and C elements, which is consistent with the results of EDS analysis. The O 1s spectra indicate that the typical metal–oxygen bond (M–O) at 530.0 eV is represented as lattice oxygen (O L ) and the peak at 531.8 eV represents surface adsorbed oxygen (O A ) (Figure B) . Interestingly, the peak of oxygen vacancies appears at 533.0 eV in CoFe 2 O 4– x (O V ) but is absent in CoFe 2 O 4 , which is due to the high temperature annealing of CoFe 2 O 4 in N 2 causing oxygen atoms to fall off to form oxygen vacancies …”

“…Figure 2F 3B). 33 Interestingly, the peak of oxygen vacancies appears at 533.0 eV in CoFe 2 O 4−x (O V ) but is absent in CoFe 2 O 4 , which is due to the high temperature annealing of CoFe 2 O 4 in N 2 causing oxygen atoms to fall off to form oxygen vacancies. 34 For the high-resolution Fe 2p spectra of CoFe 2 O 4 and CoFe 2 O 4−x , the binding energies at 710.9 and 723.6 eV were attributed to Fe 2p 3/2 and Fe 2p 1/2 , respectively (Figure 3C).…”