Influence of galvanostatic polarisation on evolution of ion concentration profiles in ion-selective membranes, studied by means of laser ablation inductively coupled plasma mass spectrometry

Ion concentration profiles and their evolution in galvanostatically polarized solvent polymeric poly(vinyl chloride) based Pb2+-selective membranes were visualized using laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS).Galvanostatic polarisation of the membrane exerts different effects depending on the lipophilic salt cation present in the membrane. For the membrane with transferable Na+ cations parallel effects of spontaneous extraction and forced Pb2+ ions incorporation were observed. However, for the membrane with non-transferable organic cations, galvanostatically forced evolution of Pb2+ concentration profiles dominates over spontaneous extraction and it can be described by linear diffusion equations related to constant flux across the membrane/solution interface.