Abstract: An ultra-high performance convergence chromatography (UPC2) method was developed to rapidly determine the residues and migration of seven isocyanate compounds in food composite packaging bags. The separation was performed on an ACQUITY UPC2 HSS C18 SB column using gradient elution with a mobile phase consisting of CO2 and methanol. The column temperature was 40 ℃, and the system back pressure was 13.10 MPa. The analytes were detected by a photo diode array (PDA) detector and quantified by an external standard method. The results showed that under the optimal conditions, baseline separation of the seven isocyanate compounds could be achieved within 2 min. The detection limits were in the range of 1.0–3.0 μg/kg, and the quantitation limits were in the ranged from 5.0 to 10.0 μg/kg. At spiked levels of 10, 125 and 625 μg/kg, the recoveries of the isocyanate compounds ranged from 85.1% to 108.4%, and the relative standard deviations (RSDs) ranged from 0.7% to 6.5%. The developed method was used to determine 40 batches of food composite packaging bag samples. Isocyanate compounds residues were found in 7 batches, among which the contents of TDI and DPI residues were relatively high, but no isocyanates were found to migrate from these positive samples. The establishment of this method can provide technical support for the determination of the residues and migration of isocyanate compounds in food composite packaging bags.

Key words: ultra-high performance convergence chromatography; food composite packaging bags; isocyanate compounds; residues; migration