Electrochemical and analytical performance of cathodically pretreated boron-doped diamond electrode for the determination of oxazolidinone antibiotic linezolid in cationic surfactant media

The electrochemical oxidation of an oxazolidinone class of antibiotic, Linezolid (LNZ) was studied in aqueous as well as aqueous/surfactant media on a commercially available boron-doped diamond (BDD) electrode pretreated cathodically. By using cyclic voltammetry, LNZ showed two couples of oxidation/reduction peak in aqueous solutions. The electrode process is pH-dependent and controlled by diffusion. The compound yielded two well-separated oxidation steps in acidic, neutral and alkaline media by employing square-wave voltammetry. The sensitivity of the voltammetric measurements was improved when the cationic surfactant, cetyltrimethylammonium bromide (CTAB) was present in the electrolyte solution at pH 4.0. In Britton-Robinson buffer containing 0.9 mM CTAB, the calibration curves were linear for both oxidation peaks (Ia and IIa) over concentration ranges of 0.25-6.41 mu g mL(-1) (0.74-19.27 mu M), with detection limits of 0.05 mu g mL(-1) (0.15 mu M) for Ia, and 0.12 mu g mL(-1) (0.34 mu M) for IIa. The practical applicability of developed methodology was tested in pharmaceutical formulations.