PVC-based bis(2-nitrophenyl)disulfide sensor for zinc ions.

A PVC membrane electrode based on bis(2-nitrophenyl)disulfide carrier exhibits a very good response for Zn(2+) in a wide concentration range (from 2.9x10(-7) to 3.2x10(-2) mol l(-1)) with a slope of 29.9+/-0.4 mV per decade of Zn(2+) concentration. The response time of the sensor is about 10 s and the membrane can be used for more than 3 months without any observed divergence in potentials. The proposed sensor exhibits very good selectivity for Zn(2+) over many cations and can be used in a wide pH range (2-9). This assembly served also as an indicator electrode in potentiometric titrations involving zinc ions and direct potentiometric determination of zinc ions in real and synthetic samples.