Nanomolar detection of lead using electrochemical methods based on a novel phthalocyanine

Abstract 4-4-[(Bromo-phenylimino)-methyl]-2-methoxy-phenoxy-phthalocyanine (CoTBrIMPPc) complex was synthesized and characterized by different spectroscopic as well as analytical techniques for the first time. The iminephthalocyanine derivative displayed redox peaks ascribed to cobalt (Co+2/Co+1) metal and phthalocyanine ligand (Pc-2/Pc-3). The (CoTBrIMPPc) complex was immobilized by drop coating method on the glassy carbon surface and the modified electrode was utilised for detecting lead (Pb) at nanomolar concentration level by voltammetry and amperometric methods. The cyclic voltammetric method showed linearity in the 100-1000 nmol L-1 range with the limit of detection (LOD) 37 nmol L-1. The addition of lead species did not show the considerable amperometric current response under normal amperometric conditions and hence experiments were performed by the modified methodology. Amperometry technique showed linearity in the 500 to 3000 nmol L-1 range, LOD value of 180 nmol L-1. The current response vs. Lead (Pb) concentration in graph by amperometric method exhibited correlation coefficient of 0.9991 and sensitivity of 0.0035 µA nM-1. The fabricated iminephthalocyanine based sensor is stable, reproducible and free of interference from other metal ion impurities in the electrolyte. The designed sensor has been employed for practical application.