ANALYSIS OF ASCORBIC ACID USING CARBON PASTE ELECTRODE MODIFIED WITH AMBERLITE LA-2 ANION EXCHANGER RESIN

• Main Author: Adriani David, Dian
• Format: Final Project
• Language: Indonesia
• Subjects: Kimia
• Online Access: https://digilib.itb.ac.id/gdl/view/34469
• Institution: Institut Teknologi Bandung

Ascorbic acid, known as vitamin C is an antioxidants found in high concentrations in red and green peppers, guava, kiwi, papaya, oranges, and strawberries. Ascorbic acid can also be found in a variety of beverages. Quantitative analysis of Vitamin C in beverages sold in the market is important for quality control purposes. One method than can be used to determine the levels of ascorbic acid is voltammetry. The sensitivity of voltammetry analysis depend on working electrode used. In this study, we developed a carbon paste modified with Amberlite LA-2 anion exchange resin for sensitive determination of I- ion. The electrode can be used to determine ascorbic acid indirectly through oxidation of I2 by ascorbic acid that produce I- ion. In the measurement I2 solution in chloroform was added in to ascorbic acid sample solution in voltammetric cell. The I- ion produced was measured voltammetrically. Amperometric determination of ascorbic acid has been conducted at the oxidation peak potential of I-. Amperometric calibration curve was linear in concentration range of 0,01-1 mM with detection limit of 2,94 µM. Determination of AA in real sample has been conducted and the results have been compare to those of UV-Vis spectrophotometry method. A good agreement has been found for both results.