Simultaneous Determination of Seven Preservatives in Beverage and Jam Using Stir Bar Sorptive Extraction and Gas Chromatography-Tandem Mass Spetrometry

A method was developed for the determination of seven preservatives in beverage and jam using stir bar sorptive extraction (SBSE) and gas chromatography-tandem mass spectrometry (GC-MS/MS). Samples were diluted with 30% NaCl solution (pH =3), and stir bar was added for sorptive extraction. After extraction, the preservatives were desorbed thermally from stir bar, followed by being trapped in cooled injection system and injected into gas chromatography by programmed temperature vaporization. Preservatives were analyzed by tandem mass spectrometry in multiple reactions monitoring. The linearities of the method were good in the range of 40 - 400 mg/L for sorbic acid and benzoic acid, 4 - 40 mg/L for p-hydroxybenzoic acid methyl, propyl, isopropyl, isobutyl esters, 0.4 - 4.0 mg/L for p-hydroxybenzoic acid heptyl ester, with correlation coefficient above 0.99. The limits of quantification of benzoic acid and sorbic acid were 37 and 47 mg/L, respectively, and p-hydroxybenzoic acid esters ranged from 0.62 - 6.67 mg/L. The average recoveries were in the range of 84.0% - 125.0%, relative standard deviations (RSDs) were in the range of 3.0% - 18.1%. The method was sensitive, and could be applied for rapid determination of seven preservatives in beverage and jam.