Multiwall carbon nanotube paste electrode with 3, 4-dihydroxy-cinnamic acid as mediator for the determination of glutathione in pharmaceutical and urine samples

A sensitive and selective electrochemical sensor for the determination of glutathione (GSH) was developed using a modified multiwall carbon nanotube paste electrode with 3, 4-dihydroxy-cinnamic acid as a mediator. This modified electrode showed very high electrocatalytic activity for the anodic oxidation of GSH. Under the optimized conditions, the electrocatalytic peak current showed a linear relationship with GSH concentration in the range of 0.5-400.0 μmol/L with a detection limit of 0.1 μmol/L GSH. The relative standard deviations for seven successive assays of 5.0 and 25.0 μmol/L GSH were 2.2% and 2.7%, respectively. The modified electrode was used for the determination of GSH compounds in real urine samples. © 2013, Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by Elsevier B.V. All rights reserved.