Simultaneous determination of seven preservatives in food by dispersive liquid-liquid microextraction coupled with gas chromatography-mass spectrometry.

A simple, rapid, inexpensive and environment-friendly method, based on dispersive liquid-liquid microextraction (DLLME) coupled with gas chromatography-mass spectrometry (GC-MS), was developed for the determination of food preservatives including benzoic acid (BA), sorbic acid (SA), dehydroacetic acid and four parabens. Optimum DLLME conditions were determined as follows: extraction solvent (chloroform) volume, 50 μL; disperser solvent (acetone) volume, 0.5 mL; NaCl amount, 0.50 g/4 mL sample solution at pH 4.0. Hydroquinone was selected as the internal standard. The calibration curves were linear in the range 0.05-10 mg L-1 for BA, SA and methylparaben, and 0.02-10 mg L-1, for the remainder. Limits of detection were in the range 0.15-0.50 mg kg-1 with enrichment factors ranging from 25 to 114 for all target analytes. Recoveries were in the range 88.7-110.5% with a relative standard deviation of less than 5%.