Determination of Propionic Acid in the Antimicrobial with CapillaryGas Chromatography by Using Internal Standard Method

A capillary gas chromatographic method for determination of propionic acid in the antimicrobial was developed and butenoic acid was selected as the internal standard substance. The samples were first extracted with ethyl acetate and then analyzed by DM-FFAP capillary gas chromatography with FID. The propionic acid and butenoic acid were separated from each other within 3 min. The calibration curve was linear over a range from 0.5 to 5.0 mg/mL with a correlation coefficient of 0.9996 and the detection limit was 5.0 mg/L. The recovery for spiked standards was between 91.7% and 99.9%（n=6）and the relative standard deviation was 3.09%. The method presented the advantages of simple pretreatment and high precision . The method can be used to test the propionic acid in the antimicrobial.