Non‐Enzymatic Amperometric Detection of H 2 O 2 on One‐Step Electrochemical Fabricated Cu 2 O/Electrochemically Reduced Graphene Oxide Nanocomposite

A novel electrochemical sensor based on mixed cubic and spherical Cu2O composited with MWCNTs-COOH for sensitive determination of acetaminophen

The use of Cu2O for construction of efficient electrochemical sensors has become a hot research topic. The morphology and structure of Cu2O nanoparticles have an important influence on their catalytic performance. Mixed cubic and spherical Cu2O particles were prepared by a chemical reduction method, which were then composited with carboxylated multi-walled carbon nanotubes (MWCNTs-COOH) through a facile ultrasonic treatment. Cu2O/MWCNTs-COOH composite was modified onto glassy carbon electrode (GCE) to construct a novel sensor (Cu2O/MWCNTs-COOH/GCE) for highly sensitive detection of acetaminophen (APAP). Under the optimized experimental conditions, Cu2O/MWCNTs-COOH/GCE exhibits a wide linear range (1-200 μM), high sensitivity (1.022 μA/μM), low detection limit (LOD, 3σ/k, 0.25 μM), great anti-interference property, reproducibility, repeatability, and stability for APAP detection. The practical applicability of Cu2O/MWCNTs-COOH/GCE was verified by determining APAP in commercial tablets (recoveries: 96.0 %-104.7 %) and spiked human serum samples (recoveries: 94.0 %-104.0 %).

Crumpled Graphene/Poly (azure I) Modified Electrode for Non-enzymatic Detection of Hydrogen Peroxide Secreted from Tumor Cells

Hydrogen peroxide (H₂O₂), an important representatives of reactive oxygen species, its aberrant expression is related to many diseases, including cancers. Therefore, it is very significant to design a reliable method for the real-time detection of endogenous H₂O₂. Herein, we describe preparing a poly (azure I)/crumpled graphene (cGN) modified electrode by an electro-polymerization method. The results showed that this electrode presented obvious electrocatalytic effect on the reduction of H₂O₂. Amperometric method was employed to monitor H₂O₂, and the amperometric response exhibited a good linear relationship with its concentration in the range of 8.0 × 10^-6 - 1.25 × 10^-3 mol/L; the detection limit reached to 6.7 × 10^-7 mol/L (S/N = 3). Furthermore, this modified also displayed good selectivity, long-term stability and a high anti-interference ability. Excitingly, the established method could be successfully used to detect H₂O₂ in human serum samples, and measured H₂O₂ secreted from living MCF-7 cells. It could have potential use in cancer diagnosis.