Simultaneous electrochemical determination of dopamine and acetaminophen using multiwall carbon nanotubes modified glassy carbon electrode

A highly sensitive method was investigated for the simultaneous determination of dopamine (DA) and acetaminophen (AP) using acid functionalized multi-wall carbon nanotubes (f-MWCNTs) modified glassy carbon electrodes (GCEs). Both DA and AP were accumulated at the surface of f-MWCNTs modified GCE (under open circuit condition for 30 s). In differential pulse voltammetry (DPV) technique both DA and AP give sensitive oxidation peaks at 125 mV and 307 mV, respectively. Under the optimized experimental conditions (such as supporting electrolyte pH, accumulation time and scanning rate, etc.) DA and AP give linear response over the range of 3–200 μmol L−1 (r = 0.992) and 3–300 μmol L−1 (r = 0.989), respectively. The lower detection limits were found to be 0.8 for DA and 0.6 μmol L−1 for AP. The interfering species such as ascorbic acid (AA), uric acid (UA) and reduced form of Nicotinamide adenine dinucleotide (NADH) showed no interference with the selective determination of DA and AP. The investigated method showed good stability, reproducibility (1.3% (DA) and 2.3% (AP)), repeatability (1.9%) and high recovery in pharmaceutical preparation (1.7% (DA) and 2.7% (AP)), and human serum (1.7% (DA) and 1.9% (AP)).