Fabrication of a Lead All Solid State Sensor for ppb Level Monitoring of Aqueous Lead Samples

A novel all-solid-state ion selective electrode (ASS-ISE) has been constructed for the determination of Pb(II) ions in complex aqueous media. The ASS-ISE is constructed of a layer of a conductive graphite-epoxy resin composite on a copper wire, further coated with a Pb(II) selective PVC membrane. The optimal PVC membrane is composed of 31% PVC, 62% nitrobenzen (NB), 2% of sodium tetraphenyl borate, and 5% of N,N՛-dimethylcyanodiaza-18-crown-6 as a selectophore (L). The studies proved the device to have a Nernstian response (i.e. 29.4±0.3 mV per decade) in a concentration range from 1.0×10-8 mol L-1 to 1.0×10-3 mol L-1, with a lower detection limit of 4.0×10-9 mol L-1. The proposed ASS-ISE was also found to possess a good Pb(II)-selectivity as opposed to various interfering cations. The device was further practically tested in the analysis of lead content of some water samples with complex matrices.