Abstract: The quantity of photoinitiators (PIs) migrated into hydrosoluble foods from packaging materials is usually very small. It is hardly detectable by using the current methods. For this reason, the article describes a new effective method for detecting the migration of PIs. In this method, the migration experiment was done in aqueous food simulation. After the PIs in printing inks used in food contact materials were extracted from the solution via solid-phase microextraction (SPME) using 65 μm polydimethylsiloxane/divinylbenzene (PDMS-DVB)-coated fiber, their migration amounts were determined by gas chromatography-mass spectrometry (GC-MS) in the selected ion monitoring mode (SIM). The PIs determined by SPME/GC-MS were benzophenone (BP), 1-hydroxycyclohexyl-phenylketone (CPK), ethyl-4-dimethyl-aminobenzoate (EDMAB), 4-methylbenzophenone (4-MBP), 2,2-dimethoxy-2-phenylacetophenone (2,2-DMPA), methyl 2-benzoylbenzoate (OMBB) and 2-ethylhexyl-4-dimethyl-aminobenzoate (EHDAB). The limits of detection (S/N=3) were between 0.0012 and 0.0069 μg/L. The linearity ranged from 0.03 to 1.0 μg/L (r2＞0.9909). The recoveries were in the range from 70.8% to 112.0% (n=3) with the relative standard deviations no more than 14.0%. Twenty samples were tested by using this developed method. The analytical results showed that BP was detected in all samples, and the migration amounts of BP were from 0.002 to 0.074 μg/dm2; 4-MBP was detected in ten samples, and the migration amounts of 4-MBP were from 0.006 to 0.019 μg/dm2; CPK was detected in three samples, and its amounts were 0.005, 0.005, 0.007 μg/dm2; 2,2-DMPA was detected as 0.009 μg/dm2 in one sample. The determination of real samples showed this method is feasible. The method is sensitive, simple and free from organic solvents. It could make reference to migrating determination of PIs in printing inks on food packaging surface.

Key words: aqueous food simulant, food-packaging material, gas chromatography-mass spectrometry (GC-MS), migration, photoinitiators, solid-phase microextraction (SPME)