Use of Wax-Impregnated Graphite Electrode in Polarography

Gaylor, V. F.; Conrad, A. L.; Landerl, J. H.

doi:10.1021/ac60122a013

Cited by 81 publications

(13 citation statements)

References 12 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The second theory, proposed by Gaylor et al (4,5) is that the primary reaction involves the loss of two electrons to give an unspecified intermediate. The latter authors based their admittedly tentative conclusions on the assumption that the reaction of hydroquinone on a graphite electrode in buffered 50% aqueous isopropanol was a two-electron process.…”

mentioning

confidence: 99%

Anodic Reactions of Simple Phenolic Compounds

Vermillion¹,

Pearl²

1964

J. Electrochem. Soc.

101

View full text Add to dashboard Cite

A study of the anodic reactions of phenols was made using the techniques of voltammetry, coulometry, and controlled potential electrolysis. It was shown that two entirely different anodic reactions are possible with phenolic compounds. The first is an electrophilic attack on the aromatic nucleus of the nonionized phenol with the irreversible removal of two electrons to give a mesomeric phenoxonium ion. As an example of this process an electrolysis of 2,6-di-tert-butyl-p-cresol in acetonitrile at a platinum anode resulted in the addition of methanol to form 2,6-di-tert-butyl-4-methyl-4-methoxy-cyclohexadienone in 65% yield. The second possible electrode reaction is the reversible removal of one electron from the phenoxide anion to give a phenoxy free radical. This process was illustrated by the electrolysis of the vanillinate anion in acetonitrile at a platinum anode to give dehydrodivanillin in 65% yield. It was found that half-wave potentials for both electrode reactions could be correlated by Hammett-type equations. Brief voltammetric experiments in 50% aqueous isopropanol on a carbon electrode indicated that both reactions could also occur in this system, depending on the pH and on the pKD of the phenol being investigated.Because of the importance of the phenolic hydroxyl group in the field of wood chemistry, an investigation of the anodic reactions of phenols was made using the techniques of voltammetry, coulometry, and controlled potential electrolysis. The literature on the voltammetry of phenols was reviewed recently by Suatoni et al. (1). Although a number of workers have made investigations of the anodic voltammetry of phenolic compounds, only a few papers have attempted to explain the mechanism of the primary electrode reaction, and these revealed two conflicting theories.The first theory, advanced by Hedenberg and Freiser (2), and supported by Ginzberg (3), is that the primary reaction involves the loss of one electron to form a phenoxy free radical. The second theory, proposed by Gaylor et al. (4,5) is that the primary reaction involves the loss of two electrons to give an unspecified intermediate. The latter authors based their admittedly tentative conclusions on the assumption that the reaction of hydroquinone on a graphite electrode in buffered 50% aqueous isopropanol was a two-electron process. However, more recent studies have indicated a strong possibility that, under these conditions, hydroquinone undergoes a one-electron transfer (6,7).If this is the case, the results of Gaylor et al. should be reinterpreted as indicating a one-electron primary electrode reaction in agreement with the results of Hedenberg and Freiser. Nevertheless, the data of Nash, Skauen, and Purdy (8) reveal variations between different phenolic compounds which would seem to preclude the possibility of a single simple mechanism. ExperimentalApparatus.--The polarograph, voltammetric cell, apparatus for constant potential electrolysis, and their use were described in detail in a previous paper (9). Platinum electrodes used in...

show abstract

mentioning

confidence: 99%

Anodic Reactions of Simple Phenolic Compounds

Vermillion¹,

Pearl²

1964

J. Electrochem. Soc.

101

View full text Add to dashboard Cite

show abstract

“…Solid electrodes based on wax impregnated graphites have been used for several decades for lowering the background current of voltammetric analysis [25]. Adeps neutralis is a specific solid fat which is often applied in pharmaceutical formulations for preparing suppository.…”

Section: Preparation Of Modified Electrodementioning

confidence: 99%

Hemin Modified Carbon Fat Electrode for Analyzing Antimalarial Endoperoxide Artemisinin in Artemisia annua

2008

View full text Add to dashboard Cite

A hemin bulk modified carbon electrode with Adeps neutralis (solid fat) as binder was developed for the determination of antimalarial endoperoxide artemisinin in plant matrix. The hemin modified electrode showed significant catalytic activity for the electrochemical reduction of artemisinin at about À 380 mV vs. Ag/AgCl in phosphate buffer solution of pH 7 by using cyclic and differential pulse voltammetry. Under optimized conditions strict linearity between artemisinin concentration and height of the cathodic catalytic current peak was observed in 4.8 Â 10 À6 -7.8 Â 10 À5 M concentration range (R ¼ 0.9991) when using differential pulse voltammetry. The detection limit was calculated as 1.4 Â 10 À6 M of artemisinin. The developed electroanalytical device is suitable for the determination of artemisinin in Artemisia annua extracts.

show abstract

“…Paraffin has been used to prepare amperometric enzyme electrodes. 20 Some workers [21][22][23][24] have described the advantage of using carbon-wax electrodes for electroanalytical purposes, especially in voltammetric and polarographic studies, including low residual currents, good reproducibility and robustness in operation. In this work, we tried to use a relatively simple embedding approach to construct immunosensors for transferrin assay in human serum.…”

Section: Introductionmentioning

confidence: 99%

Renewable amperometric immunosensor based on paraffin–graphite–transferrin antiserum biocomposite for transferrin assay

Liu

et al. 2000

Analyst

View full text Add to dashboard Cite

A renewable electrochemical immunosensor was developed for the determination of transferrin in human serum. It is based on a paraffin-graphite-transferrin antiserum biocomposite, which needs no additional curing. A competitive binding assay was used to determine transferrin in human serum with the aid of transferrin labeled with horseradish peroxidase. The assay conditions were optimized, including the loading of transferrin antiserum in the biocomposite, the amount of labeled transferrin in the incubation solution, incubation time and temperature. Serum samples were analyzed and the results demonstrate that the concentration range of determination with this system meets the demands of clinical analysis. The surface of the immunosensor can be regenerated by simply polishing to obtain a fresh immunocomposite ready to be used in a new competitive assay.

show abstract

Use of Wax-Impregnated Graphite Electrode in Polarography

Cited by 81 publications

References 12 publications

Anodic Reactions of Simple Phenolic Compounds

Anodic Reactions of Simple Phenolic Compounds

Hemin Modified Carbon Fat Electrode for Analyzing Antimalarial Endoperoxide Artemisinin in Artemisia annua

Renewable amperometric immunosensor based on paraffin–graphite–transferrin antiserum biocomposite for transferrin assay

Contact Info

Product

Resources

About