Determination and stripping of lead ions at disorganised self-assembled monolayer modified gold piezoelectrode

Deposition and stripping of lead ions at thiol based disorganised monolayer modified gold piezoelectrodes was studied by cyclic voltammetry (CV) and electrochemical quartz crystal nanobalance (EQCN). Gold electrodes modified with 3-mercaptopropionic acid and 1,3-dimercapto propane sulphonic acid were studied. Due to the proximity of the potentials for the Pb deposition and thiol reductive desorption, successful achievement of a deposition and stripping voltammetry methodology for determination of low concentrations of Pb2+ was achieved. However by comparison of the CV and EQCN data and consideration of the mass changes per mole electrons transferred in light of the other species present in solution, possible mechanisms are put forward for the desorption and stripping of Pb2+ at thiol modified gold electrodes.