One Step Synthesis of Covalent Connected Three-dimensional Graphene/Carbon Nanotube for Olaquindox Electrochemical Sensor

An electrochemical sensor based on a three-dimensional (3D) graphene/carbon nanotube (G/CNT) hybrid was developed for the sensitive detection of olaquindox (OLA). 3D G/CNT hybrid through covalent C-C bonding was fabricated by one-step synthesis using catalytic chemical vapor deposition. To construct the base of the sensor, a novel composite was fabricated by a functionalized 3D G/CNT with poly-(dimethy diallyl ammonium chloride) and Nafion via simple grind and ultrasonication dispersion methods. The electrochemical determination of OLA exhibited an oxidation peak at −0.685 V with a higher current response. Due to the effective surface area and active sites, a good linear relationship was observed between the OLA concentration and peak current over the range of 1.5 × 10−6–2.7 × 10−3 mg mL−1 with a detection limit of 6.12 × 10−8 mg mL−1 (3σ). The proposed electrochemical sensor was used to detect OLA in swine samples at a recovery ranging from 97.78% to 104.25%, which exhibits a broader prospect to supervise animal products and a high potential for food security applications.