Development of screen printed electrochemical sensors for selective detection of heavy metals

A flexible electrochemical sensor for selective detection of heavy metals was successfully fabricated using screen printing technique. The sensor consists of three electrodes: counter, working and reference electrodes printed using silver (Ag), carbon and silver/silver chloride (Ag/AgCl) inks, respectively. 1,10-phenanthroline and its derivative naphtha [2,3-a] dipyrido [3,2-h:2´,3´-f´] phenazine-5,18-dione (QDPPZ) was synthesized and drop casted on the working electrode of the printed device as sensitive layers for mercury ions (Hg²⁺) and lead ions (Pb²⁺), respectively. Cyclic voltammetry response (CV) of the electrochemical sensor towards Hg²⁺ and Pb2+ demonstrated a very low detection level of 50 μM with reduction peaks at 0.2 eV and -0.6 eV, respectively. An 87 % and 9 % change in the average peak currents were observed for the 50 μM concentration of Pb²⁺ and Hg²⁺, respectively, against a reference signal established for deionized water (DI). The response of the electrochemical sensor is analyzed and presented in this paper.