Hemin-graphene oxide-pristine carbon nanotubes complexes with intrinsic peroxidase-like activity for the detection of H2O2 and simultaneous determination for Trp, AA, DA, and UA

This paper demonstrated a simple wet-chemical strategy for synthesizing hemin-graphene oxide-pristine carbon nanotubes complexes (H-GO-CNTs) through the π-π interactions, and it was used to construct a novel dual sensor for the determination of H2O2 and the simultaneous determination of ascorbic acid (AA), dopamine (DA), uric acid (UA), and tryptophan (Trp). This sensor possesses the advantages of both hemin and GO-CNTs and exhibits several interesting properties. First, hemin has excellent catalysis and intrinsic peroxidase-like activity that can facilitate the catalytic reduction of H2O2. Second, GO can absorb the CNTs through the π-stacking interaction, thus causing pristine CNTs to stably disperse in aqueous media. Third, one-dimensional CNTs (1D) combined with 2D GO to form a 3D nanohybrid. This porous structure on the surface of the electrode can facilitate the discrimination of many species which oxidize or reduce at similar potentials. Cyclic voltammetry (CV), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and different pulse voltammetry (DPV) were employed to characterize the sensor. It exhibits good analytical performance, acceptable stability and good selectivity.