In this work, an electrochemically activated screen-printed carbon electrode modified with sodium dodecyl sulfate (aSPCE/SDS) was proposed for the simultaneous determination of paracetamol (PA), diclofenac (DF), and tramadol (TR). Changes of surface morphology and electrochemical behaviour of the electrode after the electrochemical activation with H2O2 and SDS surface modification were studied by scanning electron microscopy (SEM), cyclic voltammetry (CV), and electrochemical impedance spectroscopy (EIS). The influence of various parameters on the responses of the aSPCE/SDS such as pH and concentration of the buffer, SDS concentration, and techniques parameters were investigated. Using optimised conditions (Eacc. of -0.4 V, tacc. of 120 s, ΔEA of 150 mV, ν of 250 mV s-1, and tm of 10 ms), the aSPCE/SDS showed a good linear response in the concentration ranges of 5.0 × 10-8-2.0 × 10-5 for PA, 1.0 × 10-9-2.0 × 10-7 for DF, and 1.0 × 10-8-2.0 × 10-7 and 2.0 × 10-7-2.0 × 10-6 mol L-1 for TR. The limits of detection obtained during the simultaneous determination of PA, DF, and TR are 1.49 × 10-8 mol L-1, 2.10 × 10-10 mol L-1, and 1.71 × 10-9 mol L-1, respectively. The selectivity of the aSPCE/SDS was evaluated by examination of the impact of some inorganic and organic substances that are commonly present in environmental and biological samples on the responses of PA, DF, and TR. Finally, the differential pulse adsorptive stripping voltammetric (DPAdSV) procedure using the aSPCE/SDS was successfully applied for the determination of PA, DF, and TR in river water and serum samples as well as pharmaceuticals.
Keywords: diclofenac and tramadol; differential pulse adsorptive stripping voltammetry; electrochemically activated screen-printed carbon electrode modified with sodium dodecyl sulfate; human serum and pharmaceutical formulation samples; river water; simultaneous determination of paracetamol.