Evaluation of n-substituted aminosulfonic acid pH buffers with a morpholinic ring for cadmium and lead speciation studies by electroanalytical techniques

The electrochemical behavior of cadmium and lead 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 5-(N-morpholino)propanesulfonic acid (MOPS)] by various methods [differential pulse anodic stripping voltammetry (DPASV), differential pulse polarography (DPP) and cyclic voltammetry (CV)]. The complexation and/or adsorption properties of these pH buffers were also examined. Conclusions about the possible influences of these pH buffers on the speciation studies of cadmium and lead metal ions are drawn. MES, MOPSO and MOPS can be suitable pH buffers for determination of both metals by DPP and DPASV as they do not complex these metals and do not modify to a significant extent the reversibility of the electrochemical processes under the experimental conditions used. (C) 1999 Elsevier Science B.V. All rights reserved.