Conductometric Hg sensor based on polyaniline as transducer

Mercury is a common pollutant in natural water. Several chelating agents have been used to treat mercury poisoning. Among these agents British-anti-Lewisite (dimercaprol, 2,3-dimercapto-1-propanol, BAL) is a particularly successful antidote to inorganic mercury poisoning. In the present study a conductometric electrochemical sensor for Hg2+ ions was developed using polyaniline as the transducer as well as the immobilization matrix and BAL as the receptor for the heavy metal ion determination. There is a release of H+ ions in solution when Hg–BAL complex is formed causing an increase in the conductance of the polyaniline film. The study was performed using Hg2+ solutions of varying concentrations prepared in 10−2 M HCl solution as the supporting electrolyte. The polyaniline conductance was measured in the presence of different concentrations of Hg2+ ions. The study showed an increase in the conductance of the polyaniline film in the presence of increasing concentrations of Hg2+ ions at −0.2 V gate potential vs. SCE. This conductometric sensor showed a good sensitivity in concentrations as low as 10−12 M of Hg2+ ions.