Influence ofN-Substituted Aminosulfonic Acids with a Morpholinic Ring pH Buffers on the Redox Processes of Copper or Zinc Ions: A Contribution to Speciation Studies

Abstract

The electrochemical behavior of copper(II) or zinc(II) metal ions was investigated in the presence of different pH buffers [3-(N-morpholino)-2-hydroxypropanesulfonic acid (MOPSO), 2-(N-morpholino)ethanesulfonic acid (MES) and 3-(N-morpholino)propanesulfonic acid (MOPS)] by differential pulse anodic stripping voltammetry (DPASV) and differential pulse polarography (DPP). These studies showed that these pH buffers did not complex zinc or copper, but MOPSO and MOPS modified the reversibility of copper electrochemical DPASV and DPP (only MOPSO) responses, under the experimental conditions used. Depression of peak current for both metal ions was also observed in the presence of all pH buffers due to surface coverage of the electrode by those compounds, which was verified by alternating current voltammetry (ACV).