Determination of heavy metal poisoning antidote 2,3-dimercapto-1-propanesulfonic acid using silver solid amalgam electrode
Abstract
Voltammetric behavior of heavy metal poisoning antidote 2,3-dimercapto-1-propane-sulfonic acid (DMPS) was investigated using linear scan voltammetry (LSV), differential pulse cathodic stripping voltammetry (DPCSV), differential pulse anodic stripping voltammetry (DPASV), and elimination voltammetry with linear scan (EVLS) at a polished (p-AgSAE) and at a meniscus modified (m-AgSAE) silver solid amalgam electrode. It was confirmed that the mechanism of the electrode process involves two consecutive reductive desorptions with coupled proton/electron transfer preceded by a kinetic process prominent at higher scan rates as revealed by EVLS.
Voltammetric and complexation behavior of DMPS in the presence of Pb2+ was further investigated by DPASV and DPCSV titrations confirming reductive desorption, complex formation, and transmetalation. Optimum conditions for DPCSV were as follows: Britton-Robinson buffer (BRB) of pH 10, E-acc = -200 mV and t(acc) = 30 s for p-AgSAE and BRB of pH 5, E-acc = 0 mV and t(acc) = 15 s for m-AgSAE.
Limits of quantification (LOQs) and detection (LODs) were 0.3 and 0.1 mu mol L(-1 )at m-AgSAE and 0.8 and 0.3 mu mol L-1 at p-AgSAE, respectively. The practical applicability of the newly developed method was verified by determination of DMPS in commercial drug Dimaval and in human urine samples.