Simultaneous determination of sorbic acid, benzoic acid and parabens in foods: a new gas chromatography-mass spectrometry technique adopted in a survey on Italian foods and beverages.

A gas chromatographic-mass spectrometric technique is described for the simultaneous determination of sorbates, benzoates and other lipophilic preservatives in foods and beverages. The selected ions monitoring (SIM) technique allowed unambiguous identification of the compounds under study. This methodology eliminated all kinds of interferences from the complex food matrices which affect most routinely-used techniques, HPLC included. A very simple and time-saving extraction procedure was therefore employed, since subsequent purification steps were unnecessary, even for detection of trace levels of preservatives. The detection limits fell within the range of 100-200 pg. With this analytical technique, we have conducted a survey on sorbic acid, benzoic acid, methyl, ethyl, and propyl 4-hydroxybenzoate levels in 249 samples of foods and beverages on sale in markets in the Rome area. Samples were chosen from among those currently preserved by these additives. All compounds were also determined by a routinely-used HPLC technique for method comparison.