Intra‐ and Inter‐molecular Sulf‐ hydryl Hydrogen Bonding: Facilitating Proton Transfer Events for Determination of pH in Sea Water

Abstract

This work presents the electrochemical response of a 2‐(methylthio)phenol glassy carbon based electrode for a promising voltammetric pH sensor in both buffered and low‐buffered solutions. Electropolymerization of the redox species was performed with the resulting polymer presenting a Nernstian response in buffered media, with a sensitivity of 51 mV/pH unit. The effectiveness of the sulfhydryl bond to facilitate proton transfer from the bulk solution to the phenol molecules has been confirmed, providing an accurate pH measurement of 8.28 in sea water media, compared to that measured with a calibrated glass pH probe of 8.30.

A Calibration-Free pH Sensor Using an In-Situ Modified Ir Electrode for Bespoke Application in Seawater

“…obtained by amperometry is better-defined than the red one and the associated measurement is more reliable. Whilst amperometric pH sensors have found wide application [49][50][51][52][53][54][55], there has been only limited application of amperometric pH measurements in seawater, although Sisodia et al [56] recently reported an electropolymerised 2-(methylthio)phenol modified glassy carbon based electrode as an voltammetric pH sensor in seawater that had a sub-Nernstian response in buffers (pH = 4-9.2) of 51 mV/pH unit. The measured pH (8.28) of seawater using the electrode had a good match compared to that obtained by a conventional glass pH probe (8.30).…”