PROCESSIBLE POLYANILINE AS AN ADVANCED POTENTIOMETRIC pH TRANSDUCER. APPLICATION TO BIOSENSORS

Abstract

An advanced potentiometric pH transducer based on processible polyaniline (PCPAn) is reported on. Both glassy carbon and screen-printed carbon electrodes modified with PCPAn by dip-coating exhibited a fully reversible potentiometric response of approximately 90 mV/pH unit over the range from pH 3 to 9. Such a significantly higher potentiometric response of PCPAn-modified electrodes as compared with those of existing devices is explained on the basis of the thermodynamics of polyaniline redox reactions. The PCPAn-based pH transducers exhibit both good operational stability and prolonged shelf life and display a negligible response toward singly charged cations. The new thick-film pH transducer was employed for designing a potentiometric biosensor for urea. In the model solution which mimics blood serum, the urea-sensitive electrode has a detection limit of 10(-5) M urea and a maximum response of approximately 120 mV. The attractive performance characteristics are advantageous over those of existing pH sensors and offer great promise for sensing and biosensing applications.

Single-wall carbon nanotube-based voltammetric sensor and biosensor

“…This is consistent with the result from the optical property of SWNT . Furthermore, the pH detected by our electrochemical technique could be extended below 3 and it was wider than the reported ones (Karyakin et al, 1999;Hickman et al, 1991). All this forms the basis of pH indication.…”

“…And combination of pH transducer with enzymes enables bioanalysis of many substances. Besides the most frequently used potentiometric pH sensors (Karyakin et al, 1999;Komaba et al, 1997), amperometric or voltammetric sensors based on the shift of peak potential of the redox species have also been developed. Typically, a series of sulfide monolayers have been self-assembled onto gold electrode (Hickman et al, 1991;Lahav et al, 1998;Bardea et al, 2000;Mizutani et al, 1997;Beulen et al, 1999) to serve as a pH indicator.…”

Biosensors' Preparation to Be Used for Entrapment Method With Copolymers Polyaniline Derivatives

“…The hydrogen peroxide formed in the reaction of oxidation can be quantified by electrochemical methods and its amount is directly related with the sugar quantity. The immovilized enzymes in polypirrol have been carried out by several methods such as physical adsorption, covalent union, entrapment and electrochemical doping [2][3][4][5][6][7][8][9] . The entrapment method involves to capture the enzyme during the polymer electrosynthesis process, from a monomeric solution that contains the enzyme.…”

Multiple conducting polymer microwire sensors

“…These so-called ''chemiresistors'' are easier to implement experimentally commonly used conducting polymers are PPy (van de Leur and van der Waal 1999), PANI (McGovern et al 2005) and PEDOT-PSS (Daoud et al 2005). These polymers have been used to sense for various chemical analytes including volatile organic gases (de Melo et al 2005), alcohols (Athawale and Kulkarni 2000), industrial gases (Ameer and Adeloju 2005), glucose (Yamauchi et al 1999), ammonia (Dhawan et al 1997), ions (Linfords and Ivaska 2001), antigens (Torres-Rodriguez et al 1999) and pH values (Karyakin et al 1999). …”