Determination of Migration Amounts of 3-Chloro-1,2-Propanediol and 1,3-Dichloro-2-Propanol in Food Contact Paper Products by Gas Chromatography-Mass Spectrometry with Isotope Dilution

A method for simultaneous determination of migration amounts of 3-chloro-1,2-propanediol (3-MCPD) and 1,3-dichloro-2-propanol (1,3-DCP) in food contact paper products by gas chromatography-mass spectrometry (GC-MS) with isotope dilution was established. 4% (φ, the same below) acetic acid solution, 10% (φ, the same below) ethanol solution, 50% (φ, the same below) ethanol solution and olive oil were used as food simulators, and the migration tests of sample were conducted according to GB 5009.156-2016 and GB 31604.1-2015. The migrated sample solution of 10.00 g was extracted by 5 mL of isooctane (4% acetic acid solution, 10% ethanol solution, 50% ethanol solution) or 2 mL of methanol (olive oil), and the concentrated sample solution was prepared after being centrifuged, blown with nitrogen to nearly dry, and dissolved by 1.0 mL of internal standard solution containing 100 μg·L^-1 3-MCPD-d₅ and 1,3-DCP-d₅. Derivative reagentN,O-bis (trimethylsilalkyl) trifluoroacetamide solution containing 1% (mass fraction) trimethylchlorosilane of 20 μL was added with an airtight needle and the solution was derivatized at 80℃ for 60 min. GC-MS and internal standard method were used for quantitative analysis. As shown by the results, linear ranges of standard curves for 3-MCPD and 1,3-DCP were in the same range of 5-100 μg·L^-1, with detection limits (3s) of 1.0 μg·kg^-1. Recovery test was made on disposable paper plate sample at 3 concentration levels by standard addition method, giving results of 3-MCPD and 1,3-DCP in the ranges of 81.0%-91.2% and 82.0%-93.8%, and RSDs (n=6) of the determined values ranged from 3.2% to 6.6% and from 2.6% to 6.3%. This method has been applied for determination of migration amounts of 3-MCPD and 1,3-DCP in 10 kinds of food contact paper products. 3-MCPD was detected in 9 samples and 1,3-DCP was detected in 3 samples.