Nanocomposites in Electrochemical Sensors

This chapter is structured as follows Section 46.2 provides a brief introduction to electrochemical sensors. Section 46.3 presents three different approaches to prepare sol-gel nanocomposites for electrochemical sensing applications, giving specific examples of each of them. In Section 46.4, different types of electrochemical transducers that can be prepared using the sol-gel material fabrication processes, together with the electrochemical detection mechanisms applied, are described. Section 46.5 gives an overview of the recent literature on sol-gel nanocomposites as electrochemical sensors of different types of analytes. This chapter concludes by summarizing the main conclusions and discussing some future prospects of sol-gel nanocomposites for electrochemical sensor applications. 

Chitosan-clay bio-nanocomposites are very stable materials without significant desorption of the biopolymer when they are treated with aqueous salt solutions for long periods of time. In this way, they act as active phases of electrochemical sensors for detection of ions (Figure 1.8). The particular nanostructuration of the biopolymer in the interlayer region drives the selective uptake of monovalent versus polyvalent anions, which has been applied in electrode arrays of electronic tongues [132]. 

A sensitive and selective electrochemical analysis of the OPs methyl parathion (MPT) and 4-nitrophenol (PNP) has been carried out using a new type p-NiTSPc/p-PPD coated carbon fibre microelectrode (CFME)," and tricresyl phosphate has been determined in aqueous samples and air using a copper nanoparticles and carbon nanotubes-based electrochemical sensor. Similarly, dimethyl methylphosphonate (DMMP) and ethanol vapours have been determined using a high-performance nanocomposite material based on functionalized carbon nanotubes and polymers coated on a surface acoustic wave (SAW) device. ... 

Darder, M. Colilla, M. Ruiz-hitzky, E. (2003). Biopolymer-Clay Nanocomposites Based on Chitosan Intercalated in Montmorillonite. ChemicalMaterials. vol. 15, pp. 3774-3780. Darder, M. Colilla, M. Ruiz-Hitzky, E. (2005). Chitosan clay nanocomposites application as Electrochemical sensors. Applied Clap Science. Vol.28, pp.199-208. 

Most importantly, layered materials are currently of particular interest as supports for the immobihzation and/or intercalation of various ILs in order to prepare polymer nanocomposites [83, 84] with improved thermal and mechanical properties, nanohybrid materials for electrochemical sensors [85, 86], and efficient catalysts for the synthesis of cyclic carbonate by the cycloaddition of CO2 to allyl glycidyl ether [87] and propylene glycol methyl ether (PGME) from propylene oxide and methanol [88]. A detailed list of applications involving layered materials and ILs can be found in a recent review [16]. 

Fig. 12 A schematic diagram (not to scale) of the fabrication and application of a CuO/ MWCNT glucose sensor. CuO nanoparticles are electrochemically deposited onto the MWCNT array and the resulting nanocomposite generates electrochemical signals in the presence of glucose (Reproduced from ref. 83 with permission of Elsevier).

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