HPLC Determination of Citrus Red 2 in Fruit Juices, Fruits and Vegetables

HPLC was applied to the determination of citrus red 2 in fruit juices, fruits and vegetables. The sample was extracted with acetone-hexane (1+3) solution, and the extract was evaporated to dryness at 45 ℃. The residue obtained was dissolved in formic acid-acetonitrile (0.5+99.5) solution (saturated with n-hexane), and defatted with n-hexane. The Agilent TC C18 column was used as stationary phase, a mixture of acetonitrile and formic acid solution (0.1+99.9) mixed in the ratio of 92 to 8 by volume was used as mobile phase, and DAD at 508 nm was used in the determination. Linear relationship between values of peak area and mass concentration of citrus red 2 was obtained in the range of 0.25-10.0 mg·L-1, with lower limit of determination (10S/N) of 0.1 mg·kg-1. Test for recovery was made by addition of standard citrus red 2 at 3 different concentration levels to samples of fruit juice, orange and carrot as matrixes, values of recovery found were in the range from 96.3% to 104.0%. Values of RSD′s (n=6) found were in the range of 1.0%-3.6%.