Self-assembled Monolayers of 2-(((5-mercapto-1,3,4-thiadiazol-2-yl)imino)methyl)phenol (MTP) on Gold Surface: A Platform for Impedimetric and Potentiometric Sensing of Mercury(II)

2-(((5-mercapto-1,3,4-thiadiazol-2-yl)imino)methyl)phenol (MTP) was synthesized, self-assembled on the surface of gold (Au) electrode (Au-MTP) followed by characterization using Cyclic Voltammetry (CV) and Electrochemical Impedance Spectroscopy (EIS). CV and EIS confirmed the formation of well-organized Au-MTP SAM free from defects and pinholes. Au-MTP was further utilized as a platform for sensing of Hg2+ using EIS. The results showed sensitive and selective response of Au-MTP towards Hg2+ in the linear concentration range from 1.0×10-10 M to 1.0×10-4 M with limit of detection (LoD) of 5.6×10-11 M. Furthermore, MTP was self-assembled on gold nanoparticles (AuNPs) and MTP bound gold nanoparticles (MTP-AuNPs) so obtained were used as modifier for construction of carbon paste electrode (CPE). Hg2+-CPE exhibited Nernstian response towards Hg2+ with slope of 28.3 mV/decade in the concentration range from 1.0×10-5 M to 1.0×10-1 M with LoD 6.3×10-6 M. Both the Au-MTP and Hg2+-CPE were successfully applied for estimation of Hg2+ content in tap water samples.