A Multi-Walled Carbon Nanotube-Modified Glassy Carbon Electrode as a New Sensor for the Sensitive Simultaneous Determination of Paracetamol and Tramadol in Pharmaceutical Preparations and Biological Fluids

A chemically modified electrode was constructed based on a multi-walled carbon nanotube-modified glassy carbon electrode (MWCNTs/GCE). It was demonstrated that this sensor can be used for the simultaneous determination of the pharmaceutically important compounds paracetamol (PAR) and tramadol (TRA). The measurements were carried out by the application of differential pulse voltammetry (DPV), cyclic voltammetry (CV) and chronoamperometry (CA) methods. Application of the DPV method demonstrated that in phosphate buffer (pH 7.5) there was a linear relationship between the oxidation peak current and the concentration of PAR over the range 0.5 mu mol L(-1) to 210 mu mol L(-1). A similar linear correlation between oxidation peak current and concentration was observed for TRA over the range of 2 mu mol L(-1) to 300 mu mol L(-1). Under optimal conditions the modified electrode exhibited high sensitivity, selectivity and stability for both PAR and TRA determination, making it a suitable sensor for the simultaneous submicromolar detection of PAR and TRA in solutions. The analytical performance of this sensor has been evaluated for detection of PAR and TRA in human serum, human urine and some pharmaceutical preparations with satisfactory results.