Lead ion selective PVC membrane electrode based on 5,5'-dithiobis-(2-nitrobenzoic acid).

A PVC membrane electrode for lead ions based on 5,5'-dithiobis-(2-nitrobenzoic acid) as membrane carrier was prepared. The electrode exhibits a Nernstian response for Pb(2+) over a wide concentration range (1.0x10(-2)-4.0x10(-6) M). It has a relatively fast response time and can be used for at least 3 months without any divergence in potentials. The proposed electrode revealed good selectivities for Pb(2+) over a wide variety of other metal ions and could be used in a pH range of 2.0-7.0. It was used as an indicator electrode in potentiometric titration of lead ions and in direct determination of lead in water samples.