Electrocatalytic determination of sumatriptan on the surface of carbon-paste electrode modified with a composite of cobalt/Schiff-base complex and carbon nanotube

The electrochemical oxidation of sumatriptan on the surface of carbon paste electrode modified with multi-walled carbon nanotube and cobalt methyl-salophen complex is studied by using cyclic voltammetry and polarization studies. The results indicate that the drug is irreversibly oxidized in a one electron oxidation mechanism. It was found that the peak potential shifted negatively with increasing pH, confirms that H+ participate in the oxidation process. The electrode is shown to be very effective for the detection of sumatriptan in the presence of other biological reductant compounds. The prepared modified electrode exhibits a very good resolution between the voltammetric peaks of sumatriptan, ascorbic acid and uric acid, which makes it suitable for the simultaneous detection of sumatriptan in the presence of these compounds in clinical and pharmaceutical preparations. It can be concluded that multi-walled carbon nanotube and Shiff base complex have synergic effect on electroacatalytic oxidation of sumatriptan. A linear range of 1–1000 μM and detection limit of 0.3 μM was obtained for sumatriptan from DPV measurements using this electrode in 0.1 M acetate buffered solution of pH 5.0. The electrode has been applied successfully for the determination of sumatriptan in synthetic serum and commercial tablets.

Research highlights
► Electrocatalytic oxidation of sumatriptan at a modified carbon paste electrode was studied.
► Carbon nanotube and Cobalt Schiff base complex were used as mediators.
► The electrode was applied for determination of sumatriptan in synthetic serum and pharmaceutical preparations.
► The procedure of preparation and surface regeneration of the electrode is easy and fast.
► The renewability, reproducibility and long time stability are advantages of the electrode.