Could someone assist me, please? I'm seeking guidance on how to determine the pH value from a CV curve and convert Potential vs Ag/AgCl/KCl to pH measurements for a standard buffer solution using Optentiomentric analysis based on the CV results. Additionally, I would appreciate advice on how to ascertain pH sensing for an unknown solution utilizing a 3-electrode system (with the working electrode being GCE/Active material, reference electrode as Ag.AgCl/KCl, and counter electrode as Pt foil). Suggestions and answers supported by references would be greatly appreciated.
Thirumal Vediyappan use cyclic voltammetry to identify the pH-dependent oxidation or reduction peak. To do this, you must record voltammograms of buffers at different pHs. When you have identified it, use differential pulse voltammetry (DPV) to make measurements at different pH from 2 to 10, preferably varying the pH by one unit: 2, 3, 4...10. You must keep in mind that the potential range can vary with the pH, so you must keep changing the range of potentials or use a very wide one in DPV. With the DPV peak potential you must build a calibration curve of Ep vs. pH. Having the curve, you will be able to record the DPV voltammogram of the unknown pH sample and calculate its pH using the equation on the line.
Here you will find a reference: https://www.mdpi.com/2073-4360/12/10/2328
OCP measurements can be used for some electrodes, where a calibration plot of OCP vs. pH (buffers) can be constructed.
Regards!
Dear Javier Ernesto Vilaso Cadre, really thank you for the useful information.