A solid-state pH sensor for nonaqueous media including ionic liquids

Brianna C. Thompson*, Orawan Winther-Jensen, Bjorn Winther Jensen, Douglas R. Macfarlane

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

15 Citations (Scopus)


We describe a solid state electrode structure based on a biologically derived proton-active redox center, riboflavin (RFN). The redox reaction of RFN is a pH-dependent process that requires no water. The electrode was fabricated using our previously described 'stuffing' method to entrap RFN into vapor phase polymerized poly(3,4-ethylenedioxythiophene). The electrode is shown to be capable of measuring the proton activity in the form of an effective pH over a range of different water contents including nonaqueous systems and ionic liquids (ILs). This demonstrates that the entrapment of the redox center facilitates direct electron communication with the polymer. This work provides a miniaturizable system to determine pH (effective) in nonaqueous systems as well as in ionic liquids. The ability to measure pH (effective) is an important step toward the ability to customize ILs with suitable pH (effective) for catalytic reactions and biotechnology applications such as protein preservation.

Original languageEnglish
Pages (from-to)3521-3525
Number of pages5
JournalAnalytical Chemistry
Issue number7
Publication statusPublished - 2013 Apr 2
Externally publishedYes

ASJC Scopus subject areas

  • Analytical Chemistry


Dive into the research topics of 'A solid-state pH sensor for nonaqueous media including ionic liquids'. Together they form a unique fingerprint.

Cite this