Improvement in the performance of an electrochemical sensor for ethanol determination by chemical treatment of graphite

The present work describes the preparation and characterization of chemically treated graphite by different strategies and its use for the construction of nickel-based electrochemical sensors for ethanol determination. Chemical treatment of graphite powder was carried out under three different condi...

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Bibliographic Details
Published in:Journal of electroanalytical chemistry (Lausanne, Switzerland) Switzerland), 2020-11, Vol.877, p.114659, Article 114659
Main Authors: Nahirny, Everaldo Pedrosa, Bergamini, Márcio F., Marcolino-Junior, Luiz H.
Format: Article
Language:English
Subjects:
Carbon paste electrode
Chemical sensors
Chemical treatment
Confidence intervals
Distilled beverage
Electrical measurement
Ethanol
Ethanol determination
Fourier transforms
Graphite
Hydrogen peroxide
Nickel
Nitric acid
Oxidation
Raman spectroscopy
Spectrum analysis
Sulfuric acid
Thermogravimetry
Titration
Treated graphite
Vodka
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Summary:The present work describes the preparation and characterization of chemically treated graphite by different strategies and its use for the construction of nickel-based electrochemical sensors for ethanol determination. Chemical treatment of graphite powder was carried out under three different conditions: with nitric acid, with piranha solution (98% sulfuric acid and 30% hydrogen peroxide in the ratio of 70:30) and by the Hummers method. Treated and untreated graphite samples were characterized by scanning electron microscopy techniques (SEM), Raman spectroscopy, Fourier transform infrared spectroscopy (FTIR), x-ray diffraction (XRD) and thermogravimetry (TG). Surface chemical groups were estimated by Boehm titration. Carbon paste electrodes were constructed using untreated and treated graphite and evaluated for adsorption of nickel ions. After that, exploring the catalytic proprieties of redox pair Ni(II)/Ni(III) the device was applied towards ethanol oxidation. From all chemical treatments evaluated, samples of graphite treated by the Hummers method presented the best analytical performance. Using the best set of experimental conditions, it was observed a linear dynamic range (LDR) between 50 and 1000 μmol L−1 with a sensitivity of 42.1 μA L mmol−1 and limit of detection (LOD) and quantification (LOQ) of 15 and 50 μmol L−1, respectively. The electroanalytical application of the sensor was performed for ethanol quantification in four distilled beverage samples (vodka, cachaça, pisco and whiskey) using amperometry. The obtained results agree with a comparative method at a confidence level of 95%. Repeatability studies for five different electrodes showed an RSD of less than 10%. •Chemical treatment of graphite and its use for electrochemical sensors.•Adsorption of nickel ions in the untreated and treated graphite samples.•Catalytic properties of Ni(II)/Ni(III) redox pair towards ethanol oxidation.•Significative improvement on chemical/electrochemical features of Ni-based sensors.•Analytical method for ethanol determination in samples of distilled beverages.
ISSN:1572-6657
1873-2569
DOI:10.1016/j.jelechem.2020.114659