Polymeric Lead(II)-selective Electrode Based on N,N'-Bis-thiophen-2-ylmethylene-pyridine-2,6-diamine as an Ion Carrier

Polymeric electrodes for lead ion based on N,N'-bis-thiophen-2-ylmethylene-pyridine-2,6-diamine as an ion carrier were prepared. The membrane electrode (m-3) containing o-NPOE as a plasticizer and 50 mol% additive of ionophore gives an excellent Nernstian response (29.59 mV/decade) and the limit of detection of –log a (M) = 5.74 to Pb 2+ in Pb(NO3)2 solution at room temperature. The prepared electrode provided good sensitivity and outstanding selectivity and response for Pb 2+ over a wide variety of other metal ions in pH 7.0 buffer solutions. The good sensitivity and selectivity towards lead ion are attributed to the strong complexation of lead ion to N,N'-bis-thiophen-2-ylmethylene-pyridine-2,6-diamine which has geometrically the proper cavity to coordinate to the ligand.