Dynamic sensor concept combining electrochemical pH manipulation and optical sensing of buffer capacity

Klaus Koren*, Fabian Steininger, Silvia E. Zieger

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

Abstract

State-of-the-art electrochemical and optical sensors present distinct advantages and disadvantages when used individually. Combining both methodologies offers interesting synergies and makes it possible to exploit strengths and circumvent possible problems of the individual methods. We report a dynamic sensing concept for buffer capacity by applying water electrolysis to modulate the pH microenvironment in front of an optical pH sensor placed in a flow cell. Using this combinatory approach in a nonequilibrium readout mode allowed us to assess the concentration of different buffer species in relatively short time (1 min per measurement). Theoretical simulations of the system were performed to validate the presented method. Additionally, the dynamic measurement approach enabled in situ determination of the apparent pKa of MOPS (3-(N-morpholino)propanesulfonic acid) buffer at ambient conditions. The dynamic and combinatory approach presented here holds large potential also for other pH-active analytes.

Original languageEnglish
Pages (from-to)3822-3829
Number of pages8
JournalAnalytical Chemistry
Volume93
Issue number8
DOIs
Publication statusPublished - 2 Mar 2021

ASJC Scopus subject areas

  • Analytical Chemistry

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