SYNTHESIS OF AGNP-IMMOBILIZED NI-BTC BY ONE-POT MICROWAVE-ASSISTED METHOD FOR A NON-ENZIMATIC GLUCOSE SENSOR

• Main Author: Amri, Faesal
• Format: Theses
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/67110
• Institution: Institut Teknologi Bandung

Diabetes is a chronic disease characterized by high levels of glucose in the blood. Glucose levels in diabetics are above 6.6 mM in blood samples and 200 ?M in saliva samples. Monitoring glucose levels with sensors in saliva samples has advantages because of easy to collect sample test and more convenient for routine measurements. One of the sensors that many researchers have developed for glucose detection is an electrochemical sensor that relies on a working electrode as a material that facilitates the redox reaction process in glucose detection process. However, the measurement of glucose levels in salivary fluid samples is challenging because it requires high sensitivity. Therefore, active species are needed in the working electrode that can oxidize glucose compounds, one of which is metal-organic frameworks (MOFs). MOFs are porous materials consisting of metal ions that coordinate with organic ligands that have a large surface area and are rich in active sites. Ni-BTC type MOFs are one type of MOFs that have several different types of phases with a large surface area, are stable to heating and have good catalytic properties against glucose oxidation. However, Ni-BTC type MOFs have low conductivity, so they need to be modified into materials by immobilized conducting materials such as silver nanoparticles (AgNP@MOF) to increase their conductivity. AgNP@MOF composite was synthesized through one-pot synthesis using microwave because the particle growth was faster and more evenly distributed and silver nanoparticles could be evenly dispersed without damaging the structure of the MOFs themselves. In this study, the first was to synthesize Ni- BTC under various conditions using a microwave. The materials used are Ni(NO3)2.6H2O as a metal precursor, H3BTC as a ligand, DMF solvent and tri- ethylamine as a base. The synthesis conditions were varied at temperatures of 120oC, 130oC, 140oC for 1 hour with 200 watts of power. The AgNP@Ni-BTC composite was carried out with the same material with the addition of AgNO3 and synthesized at 130oC, 1 hour and 200 watts of power. The amount of AgNO3 added was varied, which are 0.03 mmol, 0.06 mmol and 0.09 mmol. The synthesized Ni- BTC MOF and AgNP@Ni-BTC materials were characterized using PXRD, FTIR and SEM. Carbon paste electrodes (CPE) and modified carbon paste electrodes were fabricated using graphite, Ni-BTC or AgNP@Ni-BTC materials and paraffin oil in a ratio of 6: 1: 3. Each electrode fabricated contained 0.03 grams of carbon paste. Cyclic voltammetry method was used to determine the electroactive surface area of the electrode and the performance of the electrode to the electrochemical detection of glucose. The results show that the 4%AgNP@Ni-BTC modified carbon paste electrode provides better sensor performance than Ni-BTC with a limit of detection value of 13.39 ?M, a sensitivity of 6584.89 ?A mM-1 cm-2, and a linear range of 10 – 1250 ?M. 4%AgNP@Ni-BTC modified carbon paste electrode also has better stability than Ni-BTC where the electrode can be used for two measurements and has good reproducibility with an RSD value of 1.367%. Glucose detection test on salivary fluid samples showed that 4%AgNP@Ni-BTC modified carbon paste electrode could be used to measure glucose levels in salivary fluid.