Rapid extraction and gas-liquid chromatographic determination of benzoic and sorbic acids in beverages

A rapid method for extraction and quantitative determination of sorbic and benzoic acids in carbonated drinks and fruit juices is described. Acidified sample aliquots are transferred onto an Extrelut column. Acid preservatives are then eluted from the column with a mixture of ethyl ether-petroleum ether. Content of preservatives in the concentrated ethereal extract is readily determined by temperature-programmed gas-liquid chromatography without the need to prepare derivatives.