Electrocatalytic determination of mercury cations at the interfaces of gold electrodes modified with self-assembled monolayers of cobalt phthalocyanines and electropolymerized 3-hexylthiophene films

Abstract

In-situ fabrication of gold electrodes was performed by self-assembled monolayer (SAM) formations of peripherally furan (3) or benzothiazole (4) substituted cobalt phthalocyanines followed by electropolymerization of 3-hexylthiophene (3-HT) molecules. The resultant chemically modified electrodes (CMEs) portrayed optimal electrocatalytic activities during the voltammetric detection of Hg(I) and Hg(II) cations. Operational parameters including the accumulation potential, accumulation time and pH studies were fine-tuned. Under optimized conditions, the SAMs-3|Poly(3-HT) and SAMs-4|Poly(3-HT) Au electrodes displayed linear ranges in specific examined concentration regions with detection limits of 1.48 × 10−5 and 4.06 × 10−5 M, respectively. The CMEs illustrated good selectivity when tested in the presence of other divalent cations, viz. Zn(II), Pb(II) and Cu(II). Real sample studies were carried out using a river water sample where an acceptable recovery of 104% was attained for the SAMs-3|Poly(3-HT) Au electrode.