A Liquid Membrane Mercury Selective Electrode Based on 2-(N-pipyridino Methyl)-1-Cyano Cyclohexanol as a Novel Neutral Carrier

2-(N-pipyridino methyl)-1-cyano cyclohexanol was synthesized, characterized and used as an ionophore in construction of polyvinyl chloride (PVC) potentiometric sensor for Hg2+ determination. The best result was obtained with membrane composition of PVC (29%), sodium tetraphenylborate as ionic additive (1%), 2-(N-pipyridino methyl)-1-cyano cyclohexanol (12%) and dibutylphthalate (58%). The designed electrode showed an acceptable Nernstian slope (29.1 mV/decade) for Hg2+ over a wide concentration range from 5 × 10–7 to 1 × 10–2 M with a detection limit of 2.5 × 10–7 M. The potential response was independent from pH in the range of 6.0–9.0 and the sensor response time was relatively short (~25 s). The sensor performance was invariable for at least 6 weeks. Electrode selectivity was evaluated by matched potential method. Finally, the proposed sensor was used as an indicator electrode in potentiometric titration of Hg2+ with ethylenediaminetetraacetic acid and in direct determination of mercury(II) in aqueous samples with admissible accuracy and high reproducibility.