Development of a spectrophotometric method for the measurement of thiols at trace levels
Article
Shah, A., de Biasi, V. and Camilleri, P. 1995. Development of a spectrophotometric method for the measurement of thiols at trace levels. Analytical Proceedings including Analytical Communications. 32 (4), pp. 149-153. https://doi.org/10.1039/AI9953200149
Type | Article |
---|---|
Title | Development of a spectrophotometric method for the measurement of thiols at trace levels |
Authors | Shah, A., de Biasi, V. and Camilleri, P. |
Abstract | A spectrophotometric method is described for the quantitative measurement of aliphatic and aromatic thiols. The method is based on the derivatization of thiols with 5,5′-dithiobis(2-nitrobenzoic acid), commonly known as Ellman's reagent. This results in the simultaneous formation of mixed disulfides and a common product, namely 5-mercapto-2-nitrobenzoate (referred to as thiolate anion). The latter species has an absorption maximum at 420 nm and a correspondingly high molar absorptivity (ε) in aqueous media above 10 000 l mol–1 cm–1. The method developed was optimized with respect to reaction time, the pH of the buffer in which the reagent was dissolved and the reagent concentration. Linear calibration plots of absorbance of thiolate anion as a function of concentration over the range 0 to 41 µmol l–1 were obtained for all thiols analysed. The limit of detection (S/N = 3) was 0.41 µmol l–1. Five repeated analyses of a 16 µmol l–1 solution of L-cysteine methyl ester gave a coefficient of variation of 6% with respect to the absorbance of the thiolate anion. The method was found to be well suited both for the measurement of mixtures of thiols and for the quantification of cysteine bound to polystyrene beads via a glycine ‘linker’ molecule. |
Publisher | Royal Society of Chemistry |
Journal | Analytical Proceedings including Analytical Communications |
ISSN | 0144-557X |
Publication dates | |
30 Apr 1995 | |
Publication process dates | |
Deposited | 10 Nov 2017 |
Accepted | 21 Feb 1995 |
Output status | Published |
Digital Object Identifier (DOI) | https://doi.org/10.1039/AI9953200149 |
Language | English |
https://repository.mdx.ac.uk/item/874w5
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