Effects of polymerization potential on the permselectivity of poly(o-phenylenediamine) coatings deposited on Pt–Ir electrodes for biosensor applications

Highly selective and stable microdisc biosensors for l-glutamate monitoring

“…In a previous study, it was shown that decreasing the polymerization potential for the formation of PPD at discs from 0.7 V to 0.4 V enhanced the selectivity of these electrodes [44]. In contrast to these results, Rothwell et al [29] have recently shown that decreasing the electropolymerization potential decreases the interference-rejecting capability of PPD at platinum cylinder electrodes. Regardless, the results obtained from this study and those reported earlier [44] demonstrate that lowering the potential of electropolymerization of o-PD substantially enhances the selectivity of disc-type glutamate biosensors, despite the edge-effect.…”

“…Regardless, the results obtained from this study and those reported earlier [44] demonstrate that lowering the potential of electropolymerization of o-PD substantially enhances the selectivity of disc-type glutamate biosensors, despite the edge-effect. In addition, the effect of additional layers, such as the enzyme, PEA and PEI, on the formation and structure of the polymer is still unknown, although the previously mentioned study by Rothwell et al [29] showed that PEI and GluOx did marginally decrease the outstanding AA blocking of PPD-coated platinum cylinders. Fig.…”

“…1, top) shows that the integrity of the Teflon-metal seal was not compromised significantly by the cutting procedure used to form the bare disc from the wire. Interesting aspects of the surface structure of PPD formed from the different isomers of phenylenediamine [27][28][29][30] and other electro-deposited polymers [31][32][33] have been revealed in the past by scanning electron microscopy. Crater-like features described previously for PPD formed on metal cylinders from the ortho monomer [27,30] were also evident at higher magnifications for PPD electro-deposited onto the Pt D electrode ( Fig.…”

Effect of electropolymerisation conditions on the permeability of polyphenol films deposited on a vitreous carbon electrode

“…We think that increasing the applied current and therefore the concomitant oxygen evolution increases the density of small pores (permeable for phenate and not for ferricyanide anion) to the detriment of that of large ones (permeable for both phenate and ferricyanide anions). According to Rothwell et al's suggestion [18] we intend to study these films by scanning electron microscopy to understand these effects.…”

“…Nevertheless, electropolymerisation of phenolic compounds leads to the deposition of a non-conductive film that blocks the electrode activity and prevents further removal of phenol [6][7][8][9][10][11]. Many works have shown that diffusion of electroactive species through polymeric films depends on the electropolymerisation conditions such as the monomer concentration [12], the nature of the solvent used [13], the pH and background electrolyte [14], the degree of cross-linking of the polymer chains [15], the nature of the electrode [16], the electrodeposition modes (cyclic voltammetry and potentiostatic or galvanostatic electrolysis) [12,17], the applied potential [14,18] or current [19] and the electropolymerisation time (film thickness) [12].…”