Benzoic acid, sorbic acid and dehydroacetic acid which are common food preservatives were analyzed on the Silica C18P 4E according to the official method in Japan. The result shows a good separation of the three components and the calibration curves of them show good linearity respectively in the range from 0.1 to 10μg/mL.

Sample : 1μg/mL each, 20μL
1. Benzoic acid
2. Sorbic acid
3. Dehydroacetic acid

Column       : Shodex Silica C18P 4E (4.6mmI.D. x 250mm)
Eluent       : 0.2M Potassium phosphate buffer(pH4.0)/H2O/CH3OH=5/59/36
Flow rate    : 1.0mL/min
Detector     : UV(230nm)
Column temp. : 40°C