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 mol L−1 NAC and 15.0–270 mol L−1
AC. The detection limits for NAC and AC were 0.2 mol L−1 and 10.0 mol L−1, respectively. The relative
standard deviation for seven successive assays of 1.0 and 30.0 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.