A chemically modified electrode is constructed based on multi-walled carbon nanotube modified glassy carbon electrode (MWCNTs/GCE). It is demonstrated that this sensor could be used for determination of pharmaceutical important compound tramadol (TRA). The measurements were carried out using differential pulse voltammetry (DPV), cyclic voltammetry (CV) and chronoamperometry (CA) methods. DPV experiments of various concentration of TRA showed two linear dynamic ranges. The first linear dynamic range was from 4 μM to 35 μM, and the second linear dynamic range was between 60 μM to 550 μM. A detection limit of 0.38 µM (S/N = 3) was obtained. The analytical performance of this sensor has been evaluated for the detection of TRA in human serum, human urine and some pharmaceutical preparations with satisfactory results
