Bilayered FilmModified Glassy Carbon Electrode forthe Simultaneous Determination of Paracetamol and Chloroquine in Pharmaceuticaland Biological Samples

A new, cost-effective selective and highly sensitive electrochemical sensor (poly(cobalt(II) bis(1,10-phenanthroline) and copper(I) bis(2,2-bipyrdine)), poly(Co(Phen)₂/Cu(Bip)₂)/GCE) was synthesized based on the sequential electropolymerization of diaquabis(1,10-phenanthroline) cobalt(II)iodide dehydrate ([Co(Phen)₂(H₂O)₂]I₂·2H₂O) and bis(2,2′-bipyridine)hydroxyl copper(II) iodide ([Cu(Bip)₂OH]I) at a glassy carbon electrode. The established sensor (poly(Co(Phen)₂/Cu(Bip)₂)/GCE)) was employed for the simultaneous electrochemical determination of paracetamol (PCM) and chloroquine (CQ). The established sensor was characterized by FTIR, cyclic voltammetry (CV), and electrochemical impedance spectroscopy (EIS). The electrochemical performance of unmodified GCE and poly(Co(Phen)₂/Cu(Bip)₂)/GCE was evaluated for the simultaneous voltammetric determination of PCM and CQ. Using poly(Co(Phen)₂/Cu(Bip)₂)/GCE and optimized conditions, the simultaneous square wave voltammetric determination of PCM and CQ shows linearity in the concentration range between 0.5 and 200 μM, with sensitivity of 0.389 and 0.462 μA/μM and detection limits (LOD) of (3δ/m) 4.38 × 10^–2 and 7.48 × 10^–2 μM, respectively. Poly(Co(Phen)₂/Cu(Bip)₂)/GCE showed excellent performance for the simultaneous sensing of PCM and CQ in pharmaceutical, serum, and urine samples, with spiked recoveries exceeding 98.9, 97.9, and 98.2%, respectively, demonstrating low LOD, excellent sensitivity, admirable selectivity, venerable repeatability, and long-lasting stability. Poly(Co(Phen)₂/Cu(Bip)₂)/GCE's selectivity for the simultaneous determination of PCM and CQ was shown, demonstrating excellent selectivity despite potential interferences like sulfamethoxazole (SMX), salbutamol (SBM), guanine (Gua), and atorvastatin (ATS). These results designate that poly(Co(Phen)₂/Cu(Bip)₂)/GCE exhibits admirable applicability for the simultaneous electrochemical sensing of PCM and CQ in various real samples.