scholarly journals Electrochemical Sensors for Determination of Bromate in Water and Food Samples—Review

Biosensors ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 172
Author(s):  
Sheriff A. Balogun ◽  
Omolola E. Fayemi

The application of potassium bromate in the baking industry is used in most parts of the world to avert the human health compromise that characterizes bromates carcinogenic effect. Herein, various methods of its analysis, especially the electrochemical methods of bromate detection, were extensively discussed. Amperometry (AP), cyclic voltammetry (CV), square wave voltammetry (SWV), electrochemiluminescence (ECL), differential pulse voltammetry and electrochemical impedance spectroscopy (EIS) are the techniques that have been deployed for bromate detection in the last two decades, with 50%, 23%, 7.7%, 7.7%, 7.7% and 3.9% application, respectively. Despite the unique electrocatalytic activity of metal phthalocyanine (MP) and carbon quantum dots (CQDs), only few sensors based on MP and CQDs are available compared to the conducting polymers, carbon nanotubes (CNTs), metal (oxide) and graphene-based sensors. This review emboldens the underutilization of CQDs and metal phthalocyanines as sensing materials and briefly discusses the future perspective on MP and CQDs application in bromate detection via EIS.

2019 ◽  
Vol 97 (2) ◽  
pp. 140-146
Author(s):  
Tian Gan ◽  
Zhikai Wang ◽  
Mengru Chen ◽  
Wanqiu Fu ◽  
Haibo Wang ◽  
...  

In this work, the Ag@Cu particles with yolk–shell nanostructure was prepared by facile solvothermal method, which was modified on glassy carbon electrode (GCE) to fabricate electrochemical sensor for the convenient and fast determination of p-aminobenzoic acid (PABA). The surface morphology and electrochemical properties of the as-prepared Ag@Cu nanocomposite modified electrode were characterized by scanning electron microscopy, transmission electron microscopy, chronocoulometry, and electrochemical impedance spectroscopy. Further, the electrochemical sensing of PABA was performed on the Ag@Cu/GCE using cyclic voltammetry and differential pulse voltammetry techniques, showing high catalytic activity. Under the optimal conditions, the sensor exhibited a wide linear range, high sensitivity, and low detection limit of 0.315 μmol/L for PABA. The developed sensor was also successfully applied for PABA detection in anesthetic and cosmetics with satisfactory results.


2019 ◽  
Vol 63 (1) ◽  
Author(s):  
Mehdi Jalali ◽  
Zeinab Deris Falahieh ◽  
Mohammad Alimoradi ◽  
Jalal Albadi ◽  
Ali Niazi

The electrochemical behavior of Bi+3 ions on the surface of a glassy carbon electrode, in acidic media and in the presence of tamoxifen, was investigated. Cyclic voltammetry, chronoamperometry, differential pulse voltammetry, electrochemical impedance spectroscopy, and scanning electron microscopy with energy-dispersive X-ray spectroscopy were used to find the probable mechanism contributing to the reduction of the peak height of bismuth oxidation with an increase in the concentration of tamoxifen. The obtained results show a slight interaction between the bismuth species and tamoxifen which co-deposit on the surface of glassy carbon electrode. Therefore, the reduction in the peak height of bismuth oxidation as a function of tamoxifen concentration was used to develop a new differential pulse anodic striping voltammetry method for determination of trace amount of tamoxifen. The effects of experimental parameters on the in situ DPASV of Bi+3 ions in the presence of tamoxifen shown the optimal conditions as: 2 mol L-1 H2SO4 (1% v v-1 MeOH), a deposition potential of -0.5 V, a deposition time of 60 s, and a glassy carbon electrode rotation rate of 300 rpm. The calibration curve was plotted in the range of 0.5 to 6 µg mL-1 and the limits of detection and quantitation were calculated to be 3.1 × 10-5 µg mL-1 and 1.0 × 10-4 µg mL-1, respectively. The mean, RSD, and relative bias for 0.5 µg mL-1 (n=5) were found to be 0.49 µg mL-1, 0.3%, and 2%, respectively. Finally, the proposed method was successfully used for the determination of tamoxifen in serum and pharmaceutical samples.


2019 ◽  
Vol Vol. 14, No.1 ◽  
pp. 5-14 ◽  
Author(s):  
Anastasiya Tkachenko ◽  
Mykyta Onizhuk ◽  
Oleg Tkachenko ◽  
Leliz T. Arenas ◽  
Edilson V. Benvenutt ◽  
...  

In the present study, an electrochemical sensor based on the electrode (SiMImCl/C) consisting of graphite and silica, grafted with 1-n-propyl-3-methylimidazolium chloride was used for ascorbic acid (AA) quantification in pharmaceuticals and food formulations. Cyclic voltammetry and electrochemical impedance spectroscopy were applied for electrochemical characterization of the SiMImCl/C electrode. The cyclic voltammetry study revealed that the oxidation of AA on this electrode is an irreversible process, realized by adsorption and diffusion limited step. The differential pulse voltammetry was applied to develop a procedure for the AA determination. The linear range was found to be 0.3–170 μmol L-1 and the limit of detection – 0.1 μmol L-1. The proposed SiMImCl/C electrode has long term stability and does not show electrochemical activity towards the analytes, which commonly coexist with AA. The sensor was successfully used for quantification of AA in food and pharmaceutical formulations.


2021 ◽  
Vol 5 (1) ◽  
pp. 64
Author(s):  
Youssra Aghoutane ◽  
Nezha El Bari ◽  
Zoubida Laghrari ◽  
Benachir Bouchikhi

Fenthion, an organophosphate insecticide, is a cholinesterase inhibitor and is highly toxic. An electrochemical sensor based on molecularly imprinted polymer is developed here for its detection. For this purpose, 2-aminothiophenol mixed with gold nanoparticles was immobilized on screen-printed gold electrodes. The FEN pattern was then fixed before being covered with 2-aminothiophenol. Cyclic voltammetry, differential pulse voltammetry and electrochemical impedance spectroscopy methods were used for the electrochemical characterization. The low detection limit was 0.05 mg/Kg over a range of 0.01–17.3 µg/mL. The sensor was successfully applied for the determination of FEN in olive oil samples with high recovery values.


2021 ◽  
pp. 1-10
Author(s):  
F. Jahangiri-Dehaghani ◽  
H.R. Zare ◽  
Z. Shekari

A label-free electrochemical aptasensor was constructed for the sensitive and selective determination of AFM1. For preparation of the aptasensor, the AFM1 aptamer was immobilised on the surface of a glassy carbon electrode modified with hemin encapsulated in Fe-based metal-organic frameworks (hemin@Fe-MIL-101). The morphology and the structure of Fe-MIL-101 and hemin@Fe-MIL-101 were evaluated by scanning electron microscopy, Fourier-transform infrared spectroscopy, X-ray powder diffraction and Brunauer-Emmett-Teller-N2 sorption methods. Electrochemical impedance spectroscopy and cyclic voltammetry were performed to monitor the fabrication process of the electrochemical aptasensor. The electrochemical reduction current of hemin encapsulated in Fe-MIL-101 serves as a signal for the quantitative determination of AFM1. Differential pulse voltammetry was done to determine the AFM1 concentration in the linear range of 1.0×10-1-100.0 ng/ml. The detection limit of AFM1 was estimated to be 4.6×10-2 ng/ml. Finally, the fabricated aptasensor was applied to determine AFM1 in raw and boiled milk samples.


Molecules ◽  
2019 ◽  
Vol 24 (17) ◽  
pp. 3041 ◽  
Author(s):  
Yanqing Liu ◽  
Gengxin Hu ◽  
Hongwu Wang ◽  
Su Yao ◽  
Yinjian Ye

A hybrid nanocomposite consisting of hydroxylated multi-walled carbon nanotubes (MWCNTs−OH) and cube mesoporous carbon (CMK−8) was applied in this study to construct an MWCNT−OH/CMK−8/gold electrode (GE) electrochemical sensor and simultaneously perform the electro-reduction of olaquindox (OLA) and carbadox (CBX). The respective peak currents of CBX and OLA on the modified electrode increased by 720- and 595-fold relative to the peak current of GE. The performances of the modified electrode were investigated with electrochemical impedance spectroscopy, cyclic voltammetry, and differential pulse voltammetry. Then, the modified electrodes were used for the individual and simultaneous determination of OLA and CBX. The fabricated sensor demonstrated a linear response at 0.2–500 nmol/L in optimum experimental conditions, and the detection limits were 104.1 and 62.9 pmol/L for the simultaneous determination of OLA and CBX, respectively. As for individual determination, wide linear relationships were obtained for the detected OLA with levels of 0.05–500 nmol/L with LOD of 20.7 pmol/L and the detected CBX with levels of 0.10–500 nmol/L with LOD of 50.2 pmol/L. The fabricated sensor was successfully used in the independent and simultaneous determination of OLA and CBX in spiked pork samples.


Author(s):  
Bronach Healy ◽  
Francesco Rizzuto ◽  
Marida de Rose ◽  
Tian Yu ◽  
Carmel B. Breslin

AbstractAcetaminophen is a well-known drug commonly used to provide pain relief, but it can also lead to acute liver failure at high concentrations. Therefore, there is considerable interest in monitoring its concentrations. Sensitive and selective acetaminophen electrochemical sensors were designed by cycling a glassy carbon electrode (GCE) to high potentials in the presence of β-CD in a phosphate electrolyte, or by simply activating the GCE electrode in the phosphate solution. Using cyclic voltammetry, adsorption-like voltammograms were recorded. The acetaminophen oxidation product, N-acetyl benzoquinone imine, was protected from hydrolysis, and this was attributed to the adsorption of acetaminophen at the modified GCE. The rate constants for the oxidation of acetaminophen were estimated as 4.3 × 10–3 cm2 s–1 and 3.4 × 10–3 cm2 s–1 for the β-CD-modified and -activated electrodes, respectively. Using differential pulse voltammetry, the limit of detection was calculated as 9.7 × 10–8 M with a linear concentration range extending from 0.1 to 80 μM. Furthermore, good selectivity was achieved in the presence of caffeine, ascorbic acid and aspirin, enabling the determination of acetaminophen in a commercial tablet. Similar electrochemical data were obtained for both the β-CD-modified and activated GCE surfaces, suggesting that the enhanced detection of acetaminophen is connected mainly to the activation and oxidation of the GCE. Using SEM, EDX and FTIR, no evidence was obtained to indicate that the β-CD was electropolymerised at the GCE.


2019 ◽  
Vol 9 (3) ◽  
pp. 416-422
Author(s):  
Rafael Souza Antunes ◽  
Douglas Vieira Thomaz ◽  
Luane Ferreira Garcia ◽  
Eric de Souza Gil ◽  
Vernon Sydwill Sommerset ◽  
...  

Purpose: Jenipapo fruit (Genipa americana L) is a natural source of polyphenol oxidases (PPOs) whose potential in pharmaceutical analysis is noteworthy. Henceforth, this work reports the electrochemical study of a low-cost PPO-based biosensor produced from the crude extract of Jenipapo fruits and accounts a practical approach to employ this biosensor in the determination of methyldopa and paracetamol in pharmaceutical samples. Methods: In order to investigate the electrochemical properties of the biosensor, theoretical and practical approaches were employed, and both samples and the biosensor were analyzed through electrochemical impedance spectroscopy (EIS) and voltammetric techniques, namely: differential pulse voltammetry (DPV) and cyclic voltammetry (CV). Results: showcased that the biosensor presented good analytical features, as well as low detection limits (8 μmol L-1 for methyldopa and 5 μmol L-1 for paracetamol). The relative standard deviation was less than 5% mid-assay. Conclusion: The use of this biosensor is a reliable, low cost and useful alternative in the pharmaceutic determination of phenolic drugs (e.g. methyldopa and paracetamol).


Molecules ◽  
2019 ◽  
Vol 24 (12) ◽  
pp. 2200
Author(s):  
Carlos Velasco-Medina ◽  
Patricio J. Espinoza-Montero ◽  
Marjorie Montero-Jimenez ◽  
José Alvarado ◽  
Mónica Jadán ◽  
...  

We report on two new electrochemical sensors which, coupled to differential pulse voltammetry, constitutes a useful tool for diagnosis of heavy metal pollution. The electrochemical sensors AgHgNf/Cu and the AgBiNf/Cu were obtained by deposition of bimetallic particles of AgHg or AgBi on copper electrodes covered with a Nafion (Nf) film, respectively. Micrographs of the electrode’s surface showed evenly scattered bimetallic particles, with an approximate diameter of 150 nm, embedded in the Nafion (Nf) film. In order to test the electrodes, the hydrogen evolution signal according to the Brdička reaction was measured for the determination of cysteine-rich peptides (CRp) produced by plants. To check the accuracy of the electrodes, real samples of Nicotiana tabacum cells exposed to cytotoxic levels of cadmium were tested. The AgHgNf/Cu electrode produced detection limits (DLs) of 0.088 µmol L−1 for Cysteine and 0.139µmol L−1 for Glutathione, while for the AgBiNf/Cu electrode DLs were 0.41 µmol L−1 for cysteine and 0.244 µmol L−1 for glutathione. Thus, the new electrodes could be a useful analytical electrochemical system very convenient for fieldwork. The electrodes were capable of direct, accurate, and sensitive detection of synthesized peptides, despite the complex matrix where the Nicotiana tabacum cells were grown.


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