A novel ethylenediamine-bridged cobalt (II) phthalocyanine decorated MWCNT for advanced electrochemical sensing of acetaminophen

Abstract

The design and synthesis of effective molecular catalysts are essential for the efficient electrochemical sensing of pollutants. Due to their adjustable peripheral site, cobalt phthalocyanines (CoPc) are well-known electrochemical sensors for various organic, inorganic, and biomolecular analytes. In this study, multi-walled carbon nanotubes (MWCNT) were anchored onto ethylenediamine-bridged cobalt (II) phthalocyanine (EACoPc) to form EACoPc-MWCNT in three different ratios (1:1, 1:2, and 1:5 for EACoPc and MWCNT taken). The redox-active Cobalt metal in the central cavity of the highly conjugated phthalocyanine complex and the large surface area of MWCNT facilitate the electrochemical detection of analytes in water. The structural, physical, and morphological properties of the newly developed composites were investigated using various analytical techniques. The three composites were then drop-cast onto a glassy carbon electrode (GCE) to detect acetaminophen (AC) using cyclic voltammetry (CV) and Differential Pulse Voltammetry (DPV). Among the three composites, the EACoPc-MWCNT 1:2-modified GCE was found to have the highest activity toward the AC over a linear concentration range of 10–100 μM, with a detection limit of 2.14 μM using phosphate buffer as an electrolyte. From chronoamperometric analysis, the response time of the modified electrode was found to be 3 s for 25 μM of AC. The developed electrode depicted remarkable stability and reproducibility. Under optimum conditions, the modified sensor could recognise AC from other interferents. The practical applicability of the analytically modified sensor was analyzed in real water samples using the spiking method and showed impressive recovery rates of >97 %.