Determination of tramadol in pharmaceutical forms and urine samples using a boron-doped diamond electrode

The present work describes the electroanalytical investigation and a novel voltammetric method for a cheap, fast and simple quantification of tramadol (TRH) using a boron-doped diamond (BDD) electrode. TRH displayed one well-defined, irreversible and adsorption-controlled oxidation peak at about +1.58 V ( vs. Ag/AgCl) in Britton-Robinson buffer (BR, 0.1 mol L -1 , pH 3.0) using cyclic voltammetry (CV) technique. The voltammetric responses of the oxidation peaks are dependent on pH and its sensitivity was significantly enhanced in the existence of surfactant media (sodium dodecyl sulphate, SDS). In optimized experiment conditions, employing square-wave stripping mode, it was found that there was an excellent correlation between oxidation peak current and TRH concentration in the range of 0.25 to 50.0 μg mL -1 (8.34×10 -7 -1.67×10 -4 mol L -1 ), with a detection limit of 0.072 μg mL -1 (2.40×10 -7 mol L -1 ) in 0.1 mol L -1 BR buffer (pH 3.0) solution comprising 8×10 -4 mol L -1 SDS at +1.52 V (after 30 s accumulation at open-circuit condition). The developed approach can be used for the quantification of TRH in the pharmaceutical formulations and the spiked human urine samples with acceptable recoveries.