High performance and stability of a hemoglobin-biosensor based on an ionic liquid as nonaqueous media for hydrogen peroxide monitoring

An amperometric biosensor based on hydrophilic 1-butyl-3-methylimidazolium tetrafluoroborate ([bmim][BF4]) as nonaqueous electrolyte was developed. In order to improve the performance of the biosensor operating in hydrophilic nonaqueous solution, we chose the hydrophilic matrix – dimethylformamide (DMF) + chitosan organohydrogel entrapped hemoglobin (Hb) as the film modified electrode. The modified electrode possesses outstanding electrochemical response and catalytic activity in [bmim][BF4] containing no (deliberately added) water. The resulting H2O2 biosensor shows an excellent performance with an apparent Michaelis–Menten constant (Kmapp) up to 0.68 mM and a detect limit of 1.2 × 10−4 M but a relative long response time (40 s). Furthermore, we compared the temperature effect on the current responses of the biosensor to H2O2 in ionic liquid (IL) and in aqueous buffer. A higher thermal stability was observed when the biosensor was operated in IL. The study can provide a feasible approach on developing new nonaqueous biosensor in actual detection.