A new chemically modified electrode was constructed and applied to the electro-oxidation of the oxymetholone. Also, the electrode was applied to the simple, rapid, highly selective and sensitive determination of oxymetholone (OXM) in pharmaceutical and plasma samples using square wave voltammetry (SWV). The multi-walled carbon nanotubes modified glassy carbon electrode (MWCNT/GCE) were prepared by casting of the multi-walled carbon nanotubes (MWCNT) suspension on the glassy carbon electrode surface. The limit of detection and the linear range were found to be 1.36 and 2.00–90.00 ng mL−1 of OXM, respectively. The effects of potentially interfering substances on the determination of this compound were investigated and found that the electrode is highly selective. The proposed modified electrode was used for the determination of OXM in human plasma and pharmaceutical samples. This reveals that MWCNT/GCE shows excellent analytical performance for the determination of OXM in terms of very low detection limit, high sensitivity, very good repeatability and reproducibility over other methods reported in literature.
