IMIDAZOLIUM-BASED IONIC LIQUID FUNCTIONAL MATERIALS AND THEIR APPLICATION TO ELECTROANALYTICAL CHEMISTRY - Electrochemical Nanofabrication: Principles and Applications - page 157

M) for the amperometric
analysis of hydrogen peroxide, which was superior to a similar Poly
(diallyldimethyldiammonium chloride) (PDDA)/PB multilayer in
the control experiments (Fig. 4.10). It indicated that the PFIL on the
modified electrode played an important role in the electrocatalytic
reduction of hydrogen peroxide.
Similarly, polyelectrolytes functionalized IL could be
incorporated into a sol-gel organic-inorganic hybrid material
(PFIL/sol-gel) to improve charge-transfer efficiency and substrate
diffusion in chemically modified electrodes [52]. By immobilizing
GOD on a glassy carbon electrode, an enhanced current response
toward glucose was obtained, relative to a control case without
PFIL. In addition, chronoamperometry showed that electroactive
mediators diffused at a rate 10 times higher in the apparent diffusion
coefficient in PFIL-containing matrices (Fig. 4.11). These findings
suggest a potential application in bioelectroanalytical chemistry.

range, and high sensitivity (even to 10

- 7

4.4 ELECTROLYTE-FREE ELECTROCHEMISTRY

It is common practice that electrochemical experiments should
be conducted in the presence of supporting electrolytes. However,
within last few years, the general necessity to add an excess of
supporting electrolyte has been questioned, and it is desirable
to consider even the necessity of using a supporting electrolyte
in various cases. Some promising methods for electrolyte-free
electrochemistry such as with ultramicroelectrodes (UMEs) or their
modifications with moist ion-exchange membranes such as Nafion
have been developed. We have reported an alternative pathway
by a simple PFIL-modified electrode (Fig. 4.12) [53]. The studied
PFIL material combines features of ionic liquids and traditional
polyelectrolytes. The IL part provides high ionic conductivity and
affinity to many different compounds. The polyelectrolyte part has a
good stability in aqueous solution and capability to be immobilized
on different substrates. The electrochemical properties of such a
PFIL-modified electrode assembly in supporting electrolyte-free
solution have been investigated by using an electrically neutral
electroactive species, hydroquinone (HQ) as the model compound.