Phthalocyanine sheet polymer based amperometric sensor for the selective detection of 2,4-dichlorophenol

Abstract

Cobalt phthalocyanine sheet polymer (poly-CoPc) was synthesized by the thermal condensation of cobalt tetracarboxylicacid phthalocyanine (CoTCAPc). The synthesized complex and polymer were characterized by 1H NMR, FT-IR, absorption spectroscopy, P-XRD and thermogravimetric analysis. The formation of the polymer was monitored by FT-IR spectra and the peak corresponding to –C=O and –OH of –COOH of CoTCAPc disappeared in poly-CoPc. The polymer showed highly amorphous nature with thermal stability upto 420 °C. The cyclic voltammogram of poly-CoPc exhibited redox-active behavior and the glassy carbon (GC) electrode was modified by immobilizing poly-CoPc (GC/poly-CoPc). The modified electrode was characterized by cyclic voltammetry and impedance spectroscopy and used for the electrochemical detection of 2, 4-dichlorophenol (DCP) using voltammetry and amperometric techniques. The electrocatalytic oxidation of DCP using voltammetric technique showed a linear response in the concentration range 1 to 36 μM with the limit of detection (LOD) 0.350 μM (±0.010 μM) and the sensitivity value of 0.08 μA μM−1. Further, the designed GC/poly-CoPc sensor was used to detect DCP by an amperometric technique which exhibited a linear response in the concentration range 0.5–10 μM with LOD 0.150 μM (±0.005 μM) and sensitivity value 0.0384 μA μM−1. Fabricated sensor displayed greater stability, repeatability, reproducibility and high selectivity towards the detection of DCP. Further, the designed sensor is highly selective towards the detection of DCP even in presence of various aliphatic and aromatic alochols.