Mercury Recognition: A Potentiometric Membrane Sensor based on 4-(Benzylidene amino)-3,4-dihydro-6-methyl-3-thioxo-1,2,4-triazin-5(2H)one

In this study, a Hg2+ potentiometric membrane sensor was prepared based on the highly selective complexation between 4-(benzylidene amino)-3,4-dihydro-6-methyl-3- thioxo-1,2,4-triazin-5(2H)one as ionophore and Hg2+ ion. The electrode exhibits a Nernstian response for Hg2+ over a concentration range (1.0×10-2 to 1.0×10-6 M) with a slope of 29.06±0.4 mV per decade. The limit of detection of the sensor is 6.0×10-7 M. The sensor has a relatively fast response time (~10 s) and a useful working pH range of 3.5–6.5. Interference of some cations was also evaluated. It was used as an indicator electrode in potentiometric titration of Hg2+ ion with EDTA and in direct determination of Hg2+ in water and wastewater samples. The results indicate that this electrode is sensitive for determination of Hg2+ ion.