Simultaneous determination of eleven preservatives in foods using ultrasound-assisted emulsification micro-extraction coupled with gas chromatography-mass spectrometry

A simple and rapid method based on ultrasound-assisted emulsification micro-extraction (USAEME) coupled with gas chromatography-mass spectrometry (GC-MS) has been developed and validated for simultaneous determination of eleven preservatives in foods, including benzoic acid, sorbic acid, dehydroacetic acid, dimethyl fumarate, benzyl alcohol, methyl benzoate, o-phenylphenol, methylparaben, ethylparaben, propylparaben and butylparaben. Mandelic acid and anthracene were used as internal standards. A mixed solvent of dichloromethane and ethyl acetate in the ratio of 9 : 1(v/v) was used to extract the target analytes from acidified sample solution quantitatively in the USAEME procedure. The enrichment factors (EF) ranged from 88 to 141. The linear ranges of the method were between 0.062 μg mL−1 to 100 μg mL−1 with the correlation coefficients varied from 0.9994 to 0.9999. The limits of detection (LODs) were 0.025 mg kg−1 to 1.53 mg kg−1. The intra-day and inter-day precisions (RSDs) were less than 4.96% and 6.79%, respectively. The mean recoveries ranged from 90.5% to 104.6%. The proposed method has been successfully applied to the determination of preservatives in different food samples including cake, soy sauce, vinegar, jam, ham, beverage, pickle and bean paste.