Computational modeling of functionalized multi-walled carbon nanotubes dispersed in polyethylenimine for electrochemical sensing of acetaminophen

Abstract Monte Carlo simulations were performed to evaluate the interaction between acetaminophen (ACOP) and polyethylenimine-functionalized multi-walled carbon nanotubes (PEI- f MWCNT), followed by quantum mechanics studies concerning the oxidation mechanism. Simulations demonstrated that the polymer enhances adsorption by more than 10 kcal mol −1 and that it is important to reproduce the diameter of the nanotube in the simulation models because the adsorption occurs preferentially inside the nanotube. Using square-wave voltammetry (SWV) coupled with a glassy carbon electrode (GCE) surface modified with the dispersion of f MWCNT in the presence of PEI, it was possible to develop an analytical methodology for identification and quantification of ACOP in tablets. The analytical curves were obtained for concentrations of ACOP ranging from 9.99 × 10 −8 to 6.95 × 10 −6  mol L −1 (r = 0.9953). The detection limit and quantification limit of ACOP was determined from SWV and found to be 5.58 × 10 −8  mol L −1 and 1.86 × 10 −7  mol L −1 . The method was successfully applied to real samples detection with the recovery in the range from 95.5% and 111.0% with good stability and reproducibility. Density functional calculations suggested that the oxidation mechanism of ACOP in the presence of the composite may occur in a reversible way, involving H + or H abstraction, in a different path from the metabolic reactions.