The present work describes the electroanalytical investigation and a novel voltammetric method for the cheap, fast and simple quantification of tramadol (TRH) using a boron-doped diamond 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 the cyclic voltammetry technique. The voltammetric responses of the oxidation peaks are dependent on pH and their sensitivity was significantly enhanced in the presence of surfactant media (sodium dodecyl sulphate, SDS). Under the optimized experiment conditions, employing the square-wave stripping mode, it was found that there was an excellent correlation between oxidation peak current and the TRH concentration in the range 0.25 to 50.0 ?g mL-1 (8.34?10-7?1.67?10-4 mol L-1), with a detection limit of 0.072 ?g 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 conditions). The developed approach could be used for the quantification of TRH in pharmaceutical formulations and spiked human urine samples with acceptable recoveries.
Determination of pyridoxine (vitamin B6) in pharmaceuticals and urine samples using unmodified boron-doped diamond electrode
