Synthesis of poly (3,4-ethylenedioxythiophene)/sulfonated cellulose composites in different systems for the electrochemical sensing of paracetamol

In this paper, composites of poly (3,4-ethylenedioxythiophene) (PEDOT) and sulfonated cellulose (SC) were prepared by oxidative polymerization both in CHCl₃ and H₂O using different SC contents. The structures of composites (PEDOT/SC) were characterized by Ultraviolet–Visible absorption spectroscopy (UV–Vis), Fourier-transform infrared spectroscopy, X-ray diffraction, energy-dispersive X-ray spectroscopy, and scanning electron microscopy. Electrochemical sensing using a PEDOT/SC-modified electrode was performed by the differential pulse voltammetry method. The results indicate that SC acted as a soft template for the formation of fibrous composites. Doping PEDOT with SC affected the conjugation degree and crystallinity of the resulting composites. The results showed that the PEDOT/SC composites obtained in H₂O exhibited a higher electrochemical response than those produced in CHCl₃. The composites obtained using 5 mg/mL SC in both reaction media had the best electrochemical performance. The electrochemical analysis showed that the limit of detection (LOD) for paracetamol was 0.258 μM and 0.0742 μM, with linear ranges of 0.02–4000 μM and 0.08–1580 μM for composites obtained using 5 mg/mL SC in H₂O and CHCl₃, respectively.