Voltammetric measurements were performed using an Epsilon potentiostat (BASi—Bioanalytical System, USA) and run with an electrochemical analysis software. A three-electrode configuration consisting of MWCNT/DMF/NA modified glassy carbon electrode, Ag/AgCl (3MNaCl), and a platinum foil as working, reference, and counter electrodes, respectively, were used. A C3 cell stand (BASi-Bioanalytical System, USA) was used for all the stripping analysis. For ICP-AES measurements a Shimadzu 9000 was used.