A polypyrrole-based solid-contact Pb(2+)-selective PVC-membrane electrode with a nanomolar detection limit.

Ion-selective electrodes (ISE) based on conventional plasticized PVC membranes with solid inner contact (SC) have so far had unsatisfactory lower detection limits. Here it is shown that electropolymerization of pyrrole in the presence of potassium hexacyanoferrate(II)/(III) on Pt results in adequate inner contact for SC-ISE. The nanomolar lower detection limit achieved with the Pb(2+)-selective PVC membranes investigated is comparable with values obtained with optimized internal solutions of liquid-contact ISE.