Neo, Z. H., Seah, G. E. K. K., Ng, S. H., Safanama, D., Seng, D. H. L., & Goh, S. S. (2022). Solution-Printable PEDOT Solid-Contact for Nitrate-Selective Electrodes: Enhanced Selectivity from Anion Dopant Exchange. Analytical Chemistry, 94(46), 15956–15963. https://doi.org/10.1021/acs.analchem.2c02119
Abstract:
Poly(3,4-ethylenedioxythiophene)–polyethylene glycol (PEDOT:PEG) is a conductive material adopted in bioelectronics due to its biocompatibility and stability. While PEDOT has established its utility in cationic solid-contact ion-selective electrodes (sc-ISEs), its anionic counterpart remains less explored. Herein, we report the first example of PEDOT:PEG as a solution-printable solid-contact for all-solid-state nitrate-selective electrodes and a simple ion exchange treatment which can significantly enhance nitrate selectivity. Electrochemical impedance spectroscopy revealed that the sc-ISEs with perchlorate (ClO4–)-doped PEDOT:PEG suffered a large overall resistance. Removal of the ClO4– dopant via ion exchange reduced the resistance, resulting in significant improvement in sc-ISE performance. The optimal sc-ISE exhibited near-Nernstian response (−55.8 mV/decade) across a wide dynamic range (0.1 M to 1.12 μM) and excellent Hofmeister selectivity, which was maintained after prolonged continuous usage. This simple drop-cast and ion-exchange protocol is amenable to the scalable preparation of flexible anion sc-ISEs.
License type:
Publisher Copyright
Funding Info:
This research / project is supported by the Agency of Science, Technology and Research (A*STAR) - Career Development Fund (CDF)
Grant Reference no. : C210112021