Synthesis and characterization of iron oxide nanomaterials using Horizontal Vapor Phase Crystal (HVPC) growth technique for glucose sensing application

• Main Author: De Mesa, Donna Marie B.
• Format: text
• Language: English
• Published: Animo Repository 2011
• Subjects: Ferric oxide; Glucose; Physics
• Online Access: https://animorepository.dlsu.edu.ph/etd_masteral/4071; https://animorepository.dlsu.edu.ph/context/etd_masteral/article/10909/viewcontent/CDTG005042_P.pdf
• Institution: De La Salle University

This study investigated the capability of the grown Iron Oxide nanoparticles (NPs) for faster glucose detection. Horizontal Vapor Phase Crystal (HVPC) Growth Technique was utilized in the synthesis of Iron Oxide NPs from 99.99% purity Magnetite Iron Oxide (Sigma- Aldrich) bulk material. Different parameters were varied such as the growth environment (without external magnetic field, with external magnetic field), size of the sealed tube (10cm, 12cm, 14cm), growth temperature (10000 C, 11000C, 12000C) and dwell time (8hr, 9 hr, 10 hr). Scanning electron Microscope (SEM) and Energy Dispersive X-ray (EDX) confirmed that the Iron Oxide nanowires and almost uniform size nanoparticles approximately 50nm in diameter were formed utilizing the optimum parameters such as 1000oC growth temperature, 8 hours dwell time, 12 cm size of sealed tube and the presence of external magnetic field in the growth environment. The application of the external magnetic field enhanced the Superparamagnetic (SPM) property of the grown Iron Oxide NPs above the Curie temperature. The net magnetic moment determined the direction of magnetic force of attraction present in the grown NPs. Particles to particles- chain assembly were observed in which some NPs were interconnected forming nanowires/ agglomerated nanowires in the vapor - solid phase nucleation. The magnetic field also lessened the effect of gravity which aligned the formation along the field. Glucose oxidase (GOx) and chitosan have been immobilized by physical adsorption onto electrode with Iron Oxide NPs. Amperometric electrochemical circuit setup was used to determine the glucose sensing ability of the modified electrode with iron oxide NPs while varying some factors such as glucose concentration, applied DC potential and electrolyte solution. At α = 0.05, since F(27.52 54.48) > FC(3.29 4.49), two- way ANOVA reveals that there was a significant difference between the current responses while varying the electrolytes for different modified electrodes. Among the modified electrodes, G/FeO/CH/GOx and SS/FeO/GOx showed highest sensitivity and longest limit of detection correspondingly. The correlation coefficients (ave. r = 0.74; 0.99) indicates that there was a linear relationship between the response current versus varying concentrations and applied DC potential. Iron Oxide NPs integrated in modified electrode in an amperometric- electrochemical circuit also showed low detection limit (0.008mM), fast response time (Iron Oxide NPs magnetic property was considered in the modification of the electrode for Amperometric- Electrochemical circuit for glucose sensing application since the magnetic field reinforces the attraction of the particles to the electrodes surface.