MODIFIKASI ELEKTRODA PASTA KARBON MENGGUNAKAN EKSTRAK KASAR BUAH APEL (MALUS DOMESTICA) UNTUK PENENTUAN KADAR ASAM ASKORBAT DENGAN TEKNIK VOLTAMETRI

• Main Author: Arfansah
• Format: Final Project
• Language: Indonesia
• Subjects: Kimia
• Online Access: https://digilib.itb.ac.id/gdl/view/71571
• Institution: Institut Teknologi Bandung

Ascorbic acid , commonly known as vitamin C cannot be produced naturally in human body. Human body normally obtained vitamin C from consumption of vegetables, fruits, or pharmaceutical products. Therefore analyses of vitamin C in these samples are necessary. A biosensor based on carbon paste electrode modified with crude extract of apple as a source of peroxidase enzyme has been developed to determine ascorbic acid from pharmaceutical products. The enzyme, with the present of hydrogen peroxide, oxidizes hydroquinone to paraquinone which is then reduced back to hydroquinone to produce cathodic peak. Addition of ascorbic acid reduce the value of cathodic peak proportionally to the increase of ascorbic acid concentration. This principle is used as basis for ascorbic acid determination. Calibration curve of ascorbic acid is linier in the range of 1 ppm to 10 ppm (R2 = 0,9993) with detection limit of 0,17 ppm. Analyses of ascorbic acid have a very good accuracy.