Gas-liquid chromatographic determination of sorbic acid and sodium benzoate in table sirup

A gas-liquid chromatographic method is described for the simultaneous determination of sorbic acid and sodium benzoate in table sirup. The preservatives are extracted from acidified sirup with ethyl acetate and are analyzed on a gas chromatograph equipped with a flame ionization detector and a glass column (4 ft X 4 mm id) containing 9% SP-1200 and 2% H3PO4 on Chromosorb W (AW). Coefficients of variation for sorbic acid and sodium benzoate are 0.62 and 0.41%, respectively. Analysis time is less than 20 min, with recoveries exceeding 90%.