DEVELOPMENT OF FLOW INJECTION ANALYSIS (FIA) METHOD FOR ASCORBIC ACID DETERMINATION WITH AMPEROMETRIC DETECTOR

• Main Author: SARI DEWI (NIM : 10507068); Pembimbing : Dr. Indra Noviandri, PUSPA
• Format: Final Project
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/16865
• Institution: Institut Teknologi Bandung

Ascorbic acid is a chemical compound, called vitamin C, known for its reductive properties, which is widely consumed as an antioxidant agent in foods, beverages and drugs. In addition, ascorbic acid has also been used for prevention and treatment of various diseases such as fever, infertility, cancer and AIDS. In this study, Flow Injection Analysis (FIA) method for vitamin C determination has been developed using a poly-EBT (Eriochrom black-T) modified carbon paste electrode as an amperometric detector. At this modified electrode, electrocatalytic process occurs that allows the oxidation of ascorbic acid takes place at a faster rate. Cyclic voltammogram of ascorbic acid showed an oxidation peak at 444 mV vs Ag/AgCl in phosphate buffer solution of pH 4.0. In batch method, calibration curve of the electrode was linear in the concentration range of 1 - 10 μM with detection limit of 0.29 μM. In FIA method, calibration curve was linear in concentration range of 5-50 mM. The precission of FIA measurement was very good with % coefficient of variance of 0.85% of repeated measurement of 10 mM ascorbic acid. The results of real samples analysis using FIA method were in good agreement with those obtained with UV-Vis spectrophotometry method.