Selective and sensitive determination of dopamine via suppressing ascorbic acid using an N-(1-H-indole-3yl) methylene thiazole-2-amine thin film-modified glassy carbon electrode

The selective determination of dopamine (DA) was performed using a glassy carbon (GC) electrode modified with N-(1-H-indole-3yl) methylene thiazole-2-amine (IMT2A). IMT2A was deposited on the GC electrode by cyclic voltammetry. This modified electrode demonstrated an electrocatalytic effect on the oxidation of DA in the presence of uric acid (UA) and ascorbic acid (AA) using differential pulse voltammetry (DPV) method in 0.1 M phosphate buffer solution (PBS) of pH 7. Selective determination was realized in elimination of AA response on the IMT2A-modified electrode. The oxidation peak currents increased linearly with two concentration intervals of DA at pH 7 phosphate buffer. One of them is 0.25–9.15 μM, and the other is 9.15–95.1 μM. The limit of detection (LOD) was found as 0.086 μM. The proposed electrode was applied to the determination of DA in pharmaceutical preparations and human urine sample with satisfactory results.