In the present study, a novel nano-composite potentiometric sensor for the determination trace amounts of Tl(I) was prepared containing the room temperature ionic liquid, 1-butyl-1-methylpyrrolidinium bis(trifluoromethylsulfonyl)imide, as the conducting binder, and multi-walled carbon nanotubes, TiO2 nanoparticles, graphite powder and also tri-aza dibenzosulfoxide macrocyclic ligand as efficient ionophore. For investigation of the ion-to-electron transducing ability of multi-walled carbon nanotubes, ionic liquid and TiO2 nanoparticles on the electrode surface, the electrochemical impedance spectroscopy measurements were done. Under the optimized experimental conditions, the suggested potentiometric Tl(I) sensor exhibited an excellent Nernstian slope of 59.31 mV decade− 1, with rapid response time (5 s) and a linear calibration curve that ranged from 8.50 × 10− 9 to 1.00 × 10− 2 M was obtained with a detection limit of 5.50 × 10− 9 M.
