One-pot electrodeposition of a composite film of glucose oxidase, imidazolium alkoxysilane and chitosan on a reduced graphene oxide–Pt nanoparticle/Au electrode for biosensing

A composite film of glucose oxidase (GOx), imidazolium alkoxysilane (ImAS, a silane-ionic liquid (IL) bifunctional reagent) and chitosan (CS) was electrodeposited in a one-pot manner on a reduced graphene oxide (RGO)–Pt nanoparticle (PtNP) modified Au electrode for biosensing of glucose. Cyclic voltammetry electroreduction of coexisting p -benzoquinone was used to lift the electrode-surface pH for the GOx–ImAS–CS deposition, as a result of deprotonation of CS and hydrolyzation/condensation of ImAS at lifted pH. The RGO–PtNP composite was prepared through mild room-temperature chemical reduction of graphene oxide and H 2 PtCl 6 ·6H 2 O by formic acid , as characterized by UV–visible/FT-IR/Raman spectrophotometry , scanning electron microscopy and electrochemical techniques. The GOx–ImAS–CS/RGO–PtNP/Au electrode was used for glucose biosensing by anodically detecting the enzymatically generated H 2 O 2 at 0.55   V versus SCE. Under the optimal conditions, the GOx–ImAS–CS/RGO–PtNP/Au electrode showed a linear amperometric response to glucose concentration from 2.0   μM to 5.5   mM with a sensitivity of 84.4   μA   mM −   1   cm −   2 and a limit of detection of 0.02   μM ( S / N   =   3), which is superior to GOx–CS/RGO–PtNP/Au, GOx-(IL-NH 2 )–CS/RGO–PtNP/Au, GOx-(3-aminopropyltriethoxysilane)–CS/RGO–PtNP/Au and GOx–ImAS–CS/Au electrodes as well as many reported enzyme electrodes fabricated using similar materials.