Spectrophotometric determination of hydantoin with chromotropic acid

A simple and rapid method for the spectrophotometric determination of hydantoin with chromotropic acid has been reported. In experiment, an 0. 2% indicating solution of chromotropic acid in concentrated sulfuric acid is added to the sample solution and the mixture is heated at 150°C for 4 min to form roseolic hydantoin, then the absorbance of the solution is measured at 549 nm. The results obtained are accurate and reliable. The calibration curve is linear in the range of 0∼25 mg/L. The correlation coefficient and the recovery are 0: 9998, 96. 8%∼101. 1% respectively. The determination can effectively avoid the interference of glycine which is produced by hydantoinase from hydantoin and also has good reproducibility.