Enzymatic biosensor for nitrite detection based on direct electron transfer by CPO-ILEMB/Au@MoS2/GC.

A novel nitrite electrochemical biosensor is constructed by glassy carbon electrodes (GC) coated by chloroperoxidase (CPO) -Au nanoparticles-MoS2 nanoflowers in the presence of ionic liquid, 1-ethyl-3-methylimidazolium bromide (EMB-IL). Au-MoS2 nanoflowers modified nanocomposites are synthesized using sodium carboxymethyl cellulose as reducing agent and stabilizer. The EMB-IL can effectively promote direct electron transfer between CPO and electrode surface without redox mediator. Herein, the surface concentration of CPO on the electrode surface is 1.36 × 10–10 mol cm−2, and the electron transfer coefficient and the rate constant of CPO at electrode surface are 0.87 and 2.03 s−1, respectively. The proposed nitrite electrochemical biosensor shows a wide linear range, low detection limit, and high sensitivity. The biosensor was applied to the determination of nitrite in pickled cabbage with a good accuracy and recovery. [ABSTRACT FROM AUTHOR]