Electrocatalytic detection of Hg(II) using a platinum electrode modified with composite film of cobalt(II) phthalocyanine tetra-substituted with 1-(methoxymethyl)-benzotriazole groups and co-electropolymerized polypyrrole

Abstract

The presence of mercury adversely affects the daily lives of humankind due to its acute toxicity and environmental persistence. Therefore, the development of cost-effective smart materials which can allow the real time, ultrasensitive and discriminatory monitoring of mercury concentrations in industrial and municipal water treatment plants is an imperative. It is foreseen that this proposed water quality assurance measure will be of utmost importance to identify the culprits for the wide prevalence of this heavy metal ion in the environment. Herein, a platinum electrode (Pt) was modified via the simultaneous electropolymerization of polypyrrole (PPy) and the co-electrodeposition of tetra-[4-((1H-benzotriazole)methoxy)phthalocyaninato]cobalt(II) (CoPc-Bzt, 2, (Btz = benzotriazole)). The complementary electrode modification processes were performed in a 1:1 (v: v) DMF: acetonitrile containing 1 M tetrabutylammonium hexafluorophosphate electrolyte solution over 20 cycles using cyclic voltammetry to afford the chemically modified electrode (CME), Pt|PPy/2. Differential pulse anodic stripping voltammetry (DPASV) was used to detect Hg(II) ions using the CME within a 10 µM to 100 µM linear range while calculated limits of detection and quantification (LOD and LOQ) were determined as 3.11 and 10.00 µM, respectively. The analytical performance of the CME rendered a statistically accepted percentage recovery (97.4%) whereas that of Inductively Coupled Plasma – Optical Emission Spectroscopy (ICP-OES) is 112.3%.