Estudio de la degradación de vitamina C (como ácido ascóbico) bajo diferentes métodos de almacenamiento determinación de la influencia de la luz en el principio activo en distitas presentaciones

摘要

Three vitamin supplements where used as a vitamin C source (known as ascorbic ácid, AA). The analytical method used to determine the concentration of AA was high performance liquid chromatography (HPLC) in isocratic mode. A Buck Scientific HPLC system with a C18 Pinnacle II column (Restek, United States, 5µm, 150mm x 4.6mm), at laboratory temperature (22-24°C), was used. The HPLC operated with a flow of 1 mL/ min, and a resolution of 0.5. A mobile phase of methanol:water (5.95 v/v) acidified with 6 drops of H2SO4 6M was used. The HPLC detector is UV with a wavelength of 254nm. The calibration curve was linearized on the range of AA standards (0.05-0.3 mg/mL). The retention time for AA was between 5.5-5.9. Reproducibility and repeatability was obtained for the calibration curve. The injections for the samples lasted 10 minutes each, while the standards where analyzed for 8 minutes. The expiration date was obtained for each vitamin supplement, and it was found that it exceeds the specified date on the vitamin packages. Therefore, the presence of Zinc and Magnesium in the vitamin supplements has been determined by atomic absorption as a possible reason for the slow degradation of ascorbic acid. Key words: Ascorbic acid, dehydroascorbic acid, liquid chromatography, degradation, vitamin C, vitamin supplements, atomic absorption.