Novel polymeric cobalt tetrabenzimidazole phthalocyanine for nanomolar detection of hydrogen peroxide

Abstract

An N4 macrocyclic complex of polymeric cobalt phthalocyanine substituted with a tetrabenzimidazole (poly(CoTBImPc)) moiety at the periphery was synthesized by a facile route. The redox behavior of poly(CoTBImPc) was confirmed by cyclic voltammetry and obtained redox peaks corresponding to the central metal (Co²⁺/Co¹⁺) and phthalocyanine macrocycle (Pc²⁻/Pc³⁻). Furthermore, to enhance the conductivity, surface area, and sensitivity of the synthesized poly(CoTBImPc), carbon nanotubes (CNTs) were coated on a glassy carbon electrode (GCE/CNT/poly(CoTBmIPc)). Consequently, an amperometric sensor was fabricated for hydrogen peroxide (H₂O₂), and it manifested a linear response in the concentration range of 10 to 100 nM. The limit of detection (LOD) value observed for H₂O₂ was 2 nM with the configuration of GCE/CNT/poly(CoTBIPc) using the amperometry tool. The proposed sensor displayed outstanding reproducibility, repeatability, and high stability, without losing its main catalytic properties. Furthermore, the designed sensor has high selectivity for H₂O₂ even in the presence of interfering species in the solution.