Applications of ICPs in Electroanalysis

Although less frequently considered as electrode coatings, polyphenazines, polyphenothiazines, and polyphenoxazines [48, 49] are very attractive ICPs, exploitable in some electroanalytical applications. The main interest for these materials lies in their capability to simultaneously act as both conducting polymers and redox mediators [50,51]. The applications as electrode coatings are particularly focused to the development of enzymatic sensors, both involving NAD(P)H and H2O2 detectirui [52, 53]. 

The monomers most frequently used in electroanalytical appUcatimis are reported in Fig. 2.9. Note that, unlike the monomers described so far, they all form nonlinear polymer chains. Although the exact nature of the material formed by electrochemical oxidation of these derivatives has not been clearly defined, the most plausible structures proposed consist of branched chains, only involving a few monomer units [50, 54]. 

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It is important to note that we do not want to mimic the excellent work of Inzelt in a recent monograph of this series [7] the discussion here is focused on a critical examination of the most meaningful characteristics of ICP that have actually been or that are potentially suitable to be exploited in applications of ICPs in electroanalysis. 

Applications of ICPs in Electroanalysis 2.4.1 Direct Detection of Organic Species... 

PPy is one of the most frequently used ICPs in electroanalysis [29]. This is due both to the ease of electropolymerization (also possible in aqueous solutions and within a wide pH range) and to the relatively high stability of the p-doped polymer under ambient enviromnental conditions. Furthermore, many studies reveal that this material is biocompatible [30], which constitutes a fundamental feature when considering sensors for some clinical applications. 

Despite the widespread use of PPy in electroanalysis, PTh derivatives may be considered the ICPs preferred nowadays for such an application. The main reason lies in the possibility to easily functionalize the Th ring in the p-positions in order to obtain a material characterized by specific physico-chemical properties, such as high conductivity within a wide potential window or particular interactions with species in solution. 

Among different ICPs, pristine PPy is characterized by very low band-gap values, resulting in the p-doping process occurring at relatively low potentials. The neutral polymer can be directly oxidized by oxygen present either in air or in aqueous solution. Although a majority of PPy applications in electroanalysis... 

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