Electrochemical property and analysis application of biosensors in miscible nonaqueous media - Room-temperature ionic liquid

Stable heme proteins entrapped in dimethylformamide (DMF)-chitosan organohydrogel films modified electrodes were operated in neat hydrophilic room-temperature ionic liquid (IL) [bmim][BF4] for the first time. The modified electrodes possess outstanding electrochemical response in [bmim][BF4] without adding water. The morphology studies of films were demonstrated by atomic force microscopy (AFM). UV-Vis and FTIR spectroscopy showed that the heme proteins retained their native structure in organohydrogel films. Direct electrochemistry and bioelectrocatalysis of heme protein-organohydrogel films were investigated. Several electrochemical parameters such as the charge transfer coefficients (a) and the apparent electron transfer rate constant (k(s)) of these processes were calculated by performing nonlinear regression analysis of square wave voltammetry (SWV) experimental dates. Furthermore, high electrocatalytic activity to hydrogen peroxide (H2O2) was observed, indicating that heme proteins entrapped in organohydrogel films retained their bioelectrocatalytic activities in [bmim][BF4]. Kinetic analysis of the cyclic voltammetry dates shows that heme protein-organohydrogel films operated in IL bring up to an enhancement of the biosensor sensitivity and a high affinity for H2O2. (C) 2007 Elsevier B.V. All rights reserved.