Determination of 10 photo-initiator residues in food plastic packaging by gel permeation chromatography extraction coupled with gas chromatography-mass spectrometry

摘要

An analytical method using gel permeation chromatography (GPC) coupled with gas chromatography-mass spectrometry (GC-MS) was established for the determination of 10 photo-initiators - benzophenone (BP), 2-methyl benzophenone (2-MBP), 1-hydroxycyclohexyl phenyl ketone (Irgacure 184), 3-methyl benzophenone (3-MBP), 4-methyl benzophenone (4-MBP), ethyl 4-dimethylaminobenzoate (EDB), 2,2-dimethoxy-2-phenylacetophenone (Irgacure 651), o-methyl-benzoyl benzoate (OMBB), 2-ethylhexyl-4- dimethylamino benzoate (EHA) and 2-isopropylthioxanthone (ITX) - in plastic food packaging. The plastic samples were treated with ultrasound in cyclohexane/ethyl acetate (1 : 1, v/v). The extract was cleaned up by gel permeation chromatography. The final solution was subjected to GC-MS using an external standard method for quantitation in selected ion monitoring mode. The 10 target photo-initiators showed linear recovery relationships over the concentrations of 0.005 to 0.2 mg L-1, with r(2) > 0.999. The recoveries from spiked samples (0.07 x 10(-3), 0.17 x 10(-3) and 0.33 x 10(-3) mg dm(-2) of standard) for each of the 10 photo-initiators ranged from 77.0% to 120.6%, with relative standard deviations (RSDs) of 0.5-13.9%. The limits of detection (LOD) were from 0.03 x 10(-3) mg dm(-2) to 0.12 x 10(-3) mg dm(-2). The developed extraction method is simple and yields a sufficiently pure test sample, while the analytical method meets the sensitivity and precision requirements for photo-initiator detection. This method could be routinely used to determine the levels of photo-initiator residues in plastic food packaging.