Determination of 2,4-diaminotoluene by a bionanocomposite modified glassy carbon electrode

This work describes the development of a modified glassy carbon electrode (GCE) for the selective determination of 2,4-diaminotoluene (TDA), a primary aromatic amines (PAAs) that can be formed in food packaging materials including aromatic polyurethane (PU) adhesives. The electrode's surface was modified with multi-walled carbon nanotubes (MWCNTs), MWCNTs in chitosan (CS), and gold nanoparticles (AuNPs). The highest current response was achieved with AuNPs/MWCNTs-CS/GC electrodes, which exhibited an oxidation peak of 9.87 μA by cyclic voltammetry (CV), compared with 1.39 μA of the bare GCE. A detection limit of 35 nM was estimated by amperometry experiments. The oxidation of TDA was strongly dependent on the pH of the medium, having maximum sensitivity at pH ∼ 7. From a mechanistic point of view, the diffusion coefficient of TDA (D = 6.47 × 10−4 cm2 s−1) and the number of electrons (n ≈ 2) involved in the catalytic oxidation of TDA at the surface of the AuNPs/MWCNTs-CS/GCE were determined. The practical utility of this nanocomposite modified electrode was demonstrated by migration studies from conventional food packaging materials.