Electrocatalytic determination of reduced glutathione in human erythrocytes |
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Authors: | Rita de Cássia Silva Luz Flavio Santos Damos Paulo Guimarães Gandra Denise Vaz de Macedo Auro Atsushi Tanaka Lauro Tatsuo Kubota |
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Institution: | Institute of Chemistry, UNICAMP, P.O. Box 6154, 13084-971 Campinas, SP, Brazil. |
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Abstract: | The determination of reduced glutathione (GSH) in human erythrocytes using a simple, fast and sensitive method employing a
glassy carbon electrode modified with cobalt tetrasulfonated phthalocyanine (CoTSPc) immobilized in poly(l-lysine) (PLL) film was investigated. This modified electrode showed very efficient electrocatalytic activity for anodic oxidation
of GSH, decreasing substantially the anodic overpotentials for 0.2 V versus Ag/AgCl. The modified electrode presented better
performance in 0.1 mol l−1 piperazine-N,N′-bis(2-ethanesulfonic acid) buffer at pH 7.4. The other experimental parameters, such as the concentration of CoTSPc and
PLL in the membrane preparation, pH, type of buffer solution and applied potential, were optimized. Under optimized operational
conditions, a linear response from 50 to 2,160 nmol l−1 was obtained with a high sensitivity of 1.5 nA l nmol−1 cm−2. The detection limit for GSH determination was 15 nmol l−1. The proposed sensor presented good repeatability, evaluated in terms of the relative standard deviation (1.5%) for n = 10. The modified electrode was applied for determination of GSH in erythrocyte samples and the results were in agreement
with those obtained by a comparative method described in the literature The average recovery for these fortified samples was
100 ± 1)%. Applying a paired Student’s-t test to compare these methods, we could observe that, at the 95% confidence level, there was no statistical difference between
the reference and the proposed methods. |
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Keywords: | Electrocatalytic determination Reduced glutathione Erythrocyte samples |
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