Ionic liquid-carbon composite glucose biosensor

The use of ionic liquids that are solid at room temperature such as n-octyl-pyridinium hexafluorophosphate (nOPPF(6)) is shown to be advantageous in the fabrication of new form of biocomposite materials with attractive performance over other types of composites and pastes involving non-conductive binders. The resulting IL/graphite material brings new capabilities for electrochemical devices by combining the advantages of ILs and bulk composite electrodes. The electrocatalytic properties of the ILs are not impaired by their association with the graphite powder. The marked electrocatalytic activity towards hydrogen peroxide permits effective amperometric biosensing of glucose in connection with the incorporation of glucose oxidase within the three-dimensional IL/graphite matrix. The accelerated electron transfer is coupled with low background current and improved linearity. The advantages of these IL-based biocomposite devices are illustrated from comparison to conventional mineral oil/graphite biocomposite. The influence of the IL and glucose oxidase (GOx) loading upon the amperometric and voltammetric data, as well as the electrode capacitance and resistance, is examined. The preparation of IL/graphite composites overcomes a major obstacle for creating IL-based biosensing devices and expands the scope of IL-based electrochemical devices. (C) 2008 Elsevier B.V. All rights reserved.