AMBERLITE LA2 MODIFIED CARBON PASTE ELECTRODE FOR INDIRECT DETERMINATION OF ASCORBIC ACID

• Main Author: (NIM 10505053), SHELLY
• Format: Final Project
• Language: Indonesia
• Subjects: Kimia
• Online Access: https://digilib.itb.ac.id/gdl/view/12650
• Institution: Institut Teknologi Bandung

Heterogeneous electron transfer rate of ascorbic acid oxidation on carbon paste electrode surface is slow as indicated by wide peak of its cyclic voltammogram. Therefore, it is not possible to analyze ascorbic acid with voltametric method directly using carbon paste electrode. New amperometric method using I2 as mediator for ascorbic acid analysis on Amberlite LA2 modified carbon paste electrode has been developed. This method is based on oxidation of ascorbic acid by I2, resulting in dehydroascorbic acid and I-. The I- ion formed is then oxidized on the modified carbon paste electrode. The method is very good accuracy with percent recovery of ascorbic acid between 97.19-99.49 %. Calibration curve is linear between of 0,01 uM-8 mM of ascorbic acid with detection limit of 3,37 uM. A good result was found in vitamin C sample analysis and in accordance with those of spectrophotometric methods. <br />