Application of thiacrown ethers as ligands for lead-selective electrodes

Lead-selective solvent polymeric membrane electrodes based on selected thia crown ethers, poly(vinyl chloride) (PVC), the plasticizer bis(2-ethylhexyl) phthalate ["dioctyl phthalate" (DOP)], and potassium tetrakis(p-chloropheny l)borate (KTpCPB) (50mol%, relative to the ionophore) as anionic sites are described. The potential measurements were done in the presence of acetate buffer (pH 4.00) and for successively diluted stock solutions of 10(-2) M P b(NO3)(2). Potential-pH profiles of membranes based on selected thiacrown e thers demonstrated lack of H+ interference within a wide pH range. The effe ct of the sample solution composition as well as the inner reference soluti on on the selectivity and detection range were demonstrated.