The Britton-Robinson buffer, a combination of phosphate, borate, and acetate in equal measure, was found to exert a small but finite influence on the E peak values. The concentration of the buffer was, accordingly, kept constant between 24 and 27 mM in each ion: total acetate, borate, and phosphate. The pH was varied by adding concentrated KOH or NaOH to a stock solution before adding the buffer to the electrolyte solution.
