Riboflavin-sensitized photodynamic UV spectrophotometry for ascorbic acid assay in beverages.
Jung M.Y. | Kim S.K. | Kim S.Y.
Riboflavin-sensitized photodynamic ultraviolet spectrophotometric assay of various commercial beverages was carried out. The maximum concentration of ascorbic acid for obtaining a background correction (15 min illumination and pH 7.5) was 21 microgram/mL ascorbic acid in the testing solution. The upper limit of the measurement range for a straight line in the calibration graph of standard ascorbic acid was 10 microgram/mL,(working range 0-10 microgram/mL). The results in repeatability of the method for ascorbic acid contents in commercial fruit juices and soft-drinks showed a maximum of 4% relative standard deviation. Recovery tests with known amounts of added ascorbic acid in different fruit juices and sports drink showed the recovery of added ascorbic acid was 97.5-102.3%. Indophenol, iodine and/or HPLC methods were used in parallel to ascertain the reliability of the proposed method. This type assay could be successfully applied to many commercial beverages for determination of ascorbic acid with good accuracy, precision and reliability.Show more [+] Less [-]