Long-lived solid state perchlorate ion selective sensor based on doped poly(3,4-ethylenedioxythiophene) (PEDOT) films

This work describes the development and fabrication of stable potentiometric solid state sensors for the perchlorate ion (ClO4-) based on doped poly(3,4-ethylenedioxythiophene) (PEDOT) films. PEDOT, one of the most promising conducting polymers, is extremely stable in its oxidized state. Using PEDOT(ClO4-) films as sensing material in ion selective electrodes presents a unique opportunity to create sensors having a longer lifetime compared to analogous sensors, such as those created using doped polypyrrole. Over the 8 month period of this study, the PEDOT(ClO4-) sensors exhibited a stable, linear response spanning at least five orders of magnitude in concentration (1 M to 1 X 10(-5) M perchlorate) with near-Nernstian slopes approaching -59 mV/decade of ClO4- concentration and a limit of detection of 5 x 10(-6) M. Carbon fibers and pencil leads were employed as alternative and inexpensive substrates for EDOT polymerization, addressing problems with the sensor's form (miniature size, flexibility) and cost. (c) 2005 Elsevier B.V. All rights reserved.