A sensitive and convenient electrochemical sensor was developed for the determination of glutathione by using a carbon nanotube-ionic liquid-epinephrine composite gel modified electrode. As a mediator, epinephrine exhibited an obvious electrocatalytic activity towards the oxidation of glutathione. The square wave voltammetric technique was used to detect glutathione. The oxidation peak current showed a linear relationship with the concentration of glutathione in the range of 0.1-3.0 mu M, with a detection limit of 0.04 mu M. The repeatability and reproducibility of the sensor were investigated with the relative standard deviation (RSD%) 3.7% and 4.2%, respectively. The proposed sensor was successfully applied for the determination of glutathione in urine sample and tablet. Good recovery of 94%-106% demonstrated the capability of the sensor for the determination of GSH in real samples. (C) 2015 Elsevier B.V. All rights reserved.