An electrochemical adaptation of Ellman’s test

Nekrassova, Olga; White, Paul; Threlfell, Sarah; Hignett, Geraldine; Wain, Andrew J.; Lawrence, Nathan S.; Davis, James A.; Compton, Richard G.

doi:10.1039/b202780c

Cited by 38 publications

(24 citation statements)

References 40 publications

(41 reference statements)

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“…This is due to the presence of an excess of cystamine in the working buffer which slightly decreases the sensitivity of the PB modified electrodes. However, the detection limit and linear range are similar to those obtained by Compton group with a similar approach [13] and are still good enough to allow a measurement of glutathione in real samples with a sufficient dilution factor. The same reproducibility obtained previously with cysteamine (R.S.D.…”

Section: Measurement Of Glutathione Standard Solutionssupporting

confidence: 60%

“…A similar approach was proposed by Compton's group in 2002 [13] using a two-step reaction in which DTNB and DEPD (N,N-diethyl-p-phenylenediamine) were used as reagents, with linear sweep voltammetry detection. Problems due to high concentration of interferents such as ascorbic acid or uric acid could, however, occur with this approach.…”

Section: Cysteamine Amperometric Detectionmentioning

confidence: 99%

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Glutathione amperometric detection based on a thiol–disulfide exchange reaction

Ricci¹,

Arduini²,

Tuță³

et al. 2006

Analytica Chimica Acta

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A method based on a thiol-disulfide exchange reaction is proposed for glutathione detection. The method utilises a reaction between glutathione and an excess of the disulfide cystamine which produces an equimolar concentration of the thiol cysteamine. This latter is then detected at Prussian Blue modified screen printed electrodes at an applied potential of 200 mV versus Ag/AgCl. First the cysteamine analytical parameters were optimised, resulting in a detection limit of 10 −6 mol l −1 and a linear range up to 10 −4 mol l −1 . Reproducibility (R.S.D. = 7%, n = 6) and stability (more than 30 measurements with the same electrode) were satisfactory. Then the reaction between the disulfide cystamine and the thiol glutathione was optimised and a pH of 7.4 with a concentration of cystamine of 10 −2 mol l −1 was chosen as the best conditions in terms of reaction rate and sensor sensitivity. Glutathione was then measured under the optimised conditions giving a detection limit of 2 × 10 −6 mol l −1 and a linear range up to 5 × 10 −4 mol l −1 . Blood samples were also tested in order to determine the recovery of the method. Recoveries between 92 and 103% were observed for glutathione concentrations in blood ranging from 0.5 to 3 × 10 −3 mol l −1 .

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Section: Measurement Of Glutathione Standard Solutionssupporting

confidence: 60%

Section: Cysteamine Amperometric Detectionmentioning

confidence: 99%

Glutathione amperometric detection based on a thiol–disulfide exchange reaction

Ricci¹,

Arduini²,

Tuță³

et al. 2006

Analytica Chimica Acta

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“…Therefore, a selective determination for a specific analyte in human plasma is a challenge for the electroanalytical community, since many of its constituents may be redox active, or often impede the electroanalysis. [7][8][9]36 Consequently, reports that focus on electrochemical detection in human plasma are usually coupled with a separation technique, such as HPLC. [1][2]4,8,15,17,[20][21][22][23] In our experiments, human plasma was diluted to 25% with 0.15 M PBS (pH 7.2), and an optimal catechol concentration of 1.0 mM was used, because higher concentrations resulted in coagulation.…”

Section: Detection In Human Plasmamentioning

confidence: 99%

Selective Thiol Detection in Authentic Biological Samples with the Use of Screen-printed Electrodes

Lee

Compton

2015

ANAL. SCI.

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A selective voltammetric determination of homocysteine and glutathione was applied to cell tissue culture media and human plasma via a single two-step method. The two-step method relies on the 1,4-Michael addition reaction between electro-oxidized catechol and the target thiol. Furthermore, the procedure relies on the differing reaction kinetics of the ortho-quinone with various thiol species giving different responses as a function of the scan rate. At faster scan rates homocysteine is only detected, while at slower scan rates the adduct signal reflects both homocysteine and glutathione. As a result, the quantification of both homocysteine and glutathione can be determined with a combination of both sets of data. The previous proof-of-concept (P. T. Lee, D. Lowinsohn, and R. G. Compton, Sensors, 2014, 14, 10395), is applied to the quantification of thiols in both tissue culture media and human plasma alone. Analytical parameters were determined for both homocysteine and glutathione in the respective media and the linear range. The sensitivities in tissue culture media are ca. 3 nA μM -1 and ca. 1 nA μM -1 and the limits of detections are ca. 2 μM and ca. 1 μM for homocysteine and glutathione, respectively. In human plasma, the sensitivities were determined to be 94 and 39 nA μM -1 , and the limit of detections are ca. 0.8 μM and ca. 0.8 μM for homocysteine and glutathione, respectively.

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“…The applicability of the protocol was next examined through the detection of cysteine in a growth tissue media containing a substantial selection of ingredients covering most of the essential amino acids and carbohydrates required for cell growth and hence most of the constituents liable to be encountered within authentic biological samples [60]. A standard addition protocol was adopted to enable the recovery of 5 mM cysteine within the media.…”

Section: Recovery Experimentsmentioning

confidence: 99%

Selective Electroanalytical Assay for Cysteine at a Boron Doped Diamond Electrode

2004

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The electrochemical oxidation of the cysteine-quinone adduct has been examined as a means of providing an electroanalytical cysteine specific detection protocol. The appliance of square-wave voltammetry allowed 0.5 mM as a limit of detection. The effects of various biologically relevant interferences including other thiols were studied and found to present no change in the voltammetric profile. The practical applicability and efficiency of the methodology was probed through the determination of cysteine concentration in growth tissue medium.

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An electrochemical adaptation of Ellman’s test

Cited by 38 publications

References 40 publications

Glutathione amperometric detection based on a thiol–disulfide exchange reaction

Glutathione amperometric detection based on a thiol–disulfide exchange reaction

Selective Thiol Detection in Authentic Biological Samples with the Use of Screen-printed Electrodes

Selective Electroanalytical Assay for Cysteine at a Boron Doped Diamond Electrode

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