Novel Schiff base iron(ii) phthalocyanine with composite MWCNTs on modified GCE: electrochemical sensor development for paracetamol

Abstract

The synthesis and characterization of novel peripherally tetra-substituted Schiff base iron(II) phthalocyanines (iron(II) (2Z)-2-(3-chlorobenzylidene)hydrazinecarbothiocarboxamide phthalocyanine (FeTClBCTCAPc)) are described for the first time in this study. The Schiff base ligand and FeTClBCTCAPc complex are characterized by a combination of IR, ¹H NMR, mass spectroscopy, XRD, TGA and UV-vis spectroscopy techniques. The stepwise fabrication process of the FeTClBCTCAPc@GC electrode with composite MWCNTs and its electrochemical sensing performance towards paracetamol (PA) was evaluated using cyclic voltammetry (CV), linear sweep voltammetry (LSV), chronoamperometry (CA) and differential pulse voltammetry (DPV). Compared with the MWCNT-modified electrode, the FeTClBCTCAPc@MWCNTs/GC electrode shows a better electrocatalytic activity for the oxidation of PA with lower oxidation potential and larger peak current, so the FeTClBCTCAPc@MWCNTs/GC electrode nanocomposite can be used as an enhanced sensing platform for the electrochemical determination of PA. The kinetic parameters of PA electro-oxidation at FeTClBCTCAPc@MWCNTs/GC electrodes were studied in detail, and the determination conditions were optimized. Under the optimal conditions, the oxidation peak current is linear to the PA concentration in the range (detection limit) 50–900 nM (18.5 nM) for CA, 50–500 nM (20.5 nM) for CV, 50–500 nM (15 nM) for DPV, and 50–500 nM (15.5 nM) for LSV. Based on the high sensitivity, stability and good selectivity of the FeTClBCTCAPc@MWCNTs/GC electrode, the proposed method was successfully applied to the determination of PA in commercial tablet samples, and the satisfactory results confirm the applicability of this sensor in practical analysis.