Simultaneous determination of N-acetylcysteine and acetaminophen by voltammetric method using N-(3,4-dihydroxyphenethyl)-3,5-dinitrobenzamide modified multiwall carbon nanotubes paste electrode

A new dopamine-derivative, i.e. N-(3,4-dihydroxyphenethyl)-3,5-dinitrobenzamide (N-DHPB), was synthesized and its application was investigated for the simultaneous determination of N-acetylcysteine (NAC) and acetaminophen (AC) using modified multiwall carbon nanotubes paste electrode. This modified electrode exhibited a potent and persistent electron mediating behavior followed by well separated oxidation peaks of NAC and AC. The peaks current of differential pulse voltammograms of NAC and AC increased linearly with their concentration in the ranges of 0.5-200 mu mol L-1 NAC and 15.0-270 mu mol L-1 AC. The detection limits for NAC and AC were 0.2 mu mol L-1 and 10.0 mu mol L-1, respectively. The relative standard deviation for seven successive assays of 1.0 and 30.0 mu mol L-1 NAC and AC were 1.7% and 2.2%, respectively. The proposed sensor was successfully applied for the determination of NAC in human urine, tablet, and serum samples. (C) 2010 Elsevier B.V. All rights reserved.