Tramadol (1RS, 2RS)-2-[(dimethylamine)-methyl]-1-(3-methoxy-phenyl)-cyclohexanol hydrochloride) is a centrally acting analgesic that is widely used for the treatment of moderate to severe pain (including postoperative) throughout the world. Tramadol is extremely useful in treating somatic and visceral pain, and may also be of value in the treatment of neuropathic pain [1]. A new electrochemical sensor based on a glassy carbon electrode (GCE) modified with functionalized multiwall carbon nanotubes and molecularly imprinted polymer (MIP) composed from Polypyrrole and sol-gel for determination of tramadol was developed. The integration between functionalized multiwall carbon nanotubes, conductive polymers and sol-gel technology is a way to take advantage of the properties of all materials [2,3]. The fabrication process of the sensor was characterized by cyclic voltammetry and electrochemical impedance spectroscopy. The electrode was applied to the simple, rapid, highly selective and sensitive determination of tramadol using square wave voltammetry. The experimental parameters that affect the performance of the MIP sensor were optimized. Under the optimized conditions calibration curve of the imprinted sensor had two linear concentration ranges from 0.2 to 2.0 nM and 2.0 to 20.0 nM. The effects of potentially interfering substances on the determination of tramadol were investigated and it was found that the electrode is highly selective. Furthermore, the proposed method was successfully applied for determination of tramadol in real samples.

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