Voltammetric determination of paracetamol, tramadol and caffeine using poly(Nile blue) modified glassy carbon electrode

• A poly (Nile blue) modified glassy carbon electrode was fabricated.
• The modified electrode was used to determine Paracetamol, Tramadol and Caffeine for the first time.
• The modified electrode showed catalytic activities towards the electro oxidation of Paracetamol, Tramadol and Caffeine.
• Good sensitivity and low detection limits makes this method suitable for the determination of these compounds in real samples.

A poly(Nile blue) modified glassy carbon electrode (PNBMGCE) was fabricated by electropolymerisation of Nile blue (NB) monomer using cyclic voltammetry (CV) and was used for the determination of paracetamol (ACOP), tramadol (TRA) and caffeine (CAF). The electrochemical investigations showed that PNB — film formed on the surface of glassy carbon electrode (GCE) improved the electroactive surface area and displayed a remarkable increase in the peak current and a substantial decrease in over potential of ACOP, TRA and CAF when compared to bare GCE. The dependence of peak current and potential on pH, sweep rate and concentration were also investigated at the surface of PNBMGCE. It showed good sensitivity and selectivity in a wide linear range from 2.0 × 10–7 to 1.62 × 10–5 M, 1.0 × 10–6 to 3.1 × 10–4 M and 8.0 × 10–7 to 2.0 × 10–5 M, with detection limits of 0.08, 0.5 and 0.1 μM, for ACOP, TRA and CAF, respectively. The PNBMGCE was also successfully applied for the determination of ACOP, TRA and CAF in pharmaceutical dosage forms.