Bismuth particles Nafion covered boron-doped diamond electrode for simultaneous and individual voltammetric assays of paracetamol and caffeine

The paper concerns a sensitive and selective voltammetric method of simultaneous or separated detection of paracetamol and caffeine at a non-toxic bismuth particles Nafion covered boron-doped diamond electrode. The bismuth particles were deposited by an in situ method at Nafion covered boron-doped diamond electrode from 0.1 mol L−1 sulphuric acid solution containing metal ions and different concentrations of paracetamol and caffeine. The obtained oxidation peaks of paracetamol and caffeine appear at 0.78 and 1.44 V (vs. Ag/AgCl), respectively. The obtained detection limits for paracetamol and caffeine were 2.62 × 10−8 and 1.14 × 10−9 mol L−1, respectively. The proposed voltammetric method was applied in simultaneous determination of paracetamol and caffeine in pharmaceutical and individual detection of caffeine in beverages (energy drinks, cola beverages, tea and coffee) and weight loss supplements. The obtained results were found to be satisfactory.