GPC-GC Determination of 6 Preservatives in Bean Paste

A method of GC for determination of 6 preservatives, including sorbic acid, benzoic acid, methyl p-hydroxybenzoate, ethyl p-hydroxybenzoate, propyl p-hydroxybenzoate and butyl p-hydroxybenzoate, in bean paste was proposed. The sample was extracted with acetonitrile, and the extracts obtained were purified to remove the macromolecular impurities by gel permeation chromatography (GPC), using the Biobeads S-X3 GPC column and a mixed solvent of ethyl acetate and cyclohexane (1+1) as mobile phase. The 6 preservatives were separated on Rxi-17 (0.25 mm×30 m, 0.25 μm) capillary column and determined by FID detector. Linear relationships between values of peak area and mass concentration of the 6 preservatives were kept in the same range of 10.0-400 mg·L-1, with detection limits (3S/N) in the range of 0.56-0.74 mg·kg-1. Recovery and precision of the method were tested at 3 concentration levels, giving results of recovery in the range of 91.4%-98.8%, and RSD′s (n=5) in the range of 2.9%-5.3%.