Abstract

The electrooxidation of isoproterenol (ISPT), acetaminophen (AC) and tryptophan (Trp) and their mixture has been studied using an 8,9-dihydroxy-7-methyl-12H-benzothiazolo[2,3-b]quinazolin-12-one modified multiwall carbon nanotubes paste electrode (DMBQ-MCNTPE). The novel sensor exhibited potent and persistent electron mediating behavior followed by well separated oxidation peaks towards ISPT, AC and Trp with activation over-potential. The peak currents were linearly dependent on ISPT, AC and Trp concentrations using square wave voltammetry (SWV) method in the range of 0.04–400, 5.0–500, and 10.0–800 μmol L⁻¹, with detection limits of 0.009, 1.0, and 4.0 μmol L⁻¹, respectively. The modified electrode was used for the determination of ISPT, AC and Trp in biological and pharmaceutical samples.