Self-assembled mercapto-compound-gold-nanoparticle-modified carbon paste electrode for potentiometric determination of cadmium(II)

A new modified carbon paste electrode (CPE) based on a recently synthesized ligand [2-mercapto-5-(3-nitrophenyl)-1,3,4-thiadiazole] (MNT), self-assembled to gold nanoparticles (GNP) as suitable carrier for Cd(II) ion with potentiometric method are described. The proposed electrode exhibits a Nernstian slope of 29.4 +/- 1.0 mV per decade for Cd(II) ion over a wide concentration range from 3.1 x 10(-8) to 3.1 x 10(-4) mol L-1. The detection limit of electrode was 2.0 x 10(-8) mol L-1 of cadmium ion. The potentiometric responses of electrode based on MNT is independent of the pH of test solution in the pH range 2.0-4.0. It has quick response with response time of about 6 s. The proposed electrode show fairly good selectivity over some alkali, alkaline earth, transition and heavy metal ions. Finally, the proposed electrode was successfully employed to detect Cd(II) ion in hair and water samples.