Determination of Migrations of 28 Organic Compounds in Painted Chopsticks by Gas Chromatography-Mass Spectrometry and Research of Their Migration Rules and Risk Assessment

In view of the lacks of relevant standards for the determination of migrations of organic compounds such as alcohols, ketones and esters in painted chopsticks, and literatures about migration rules and risk assessment of the targets, the method as mentioned by the article was studied. Considering that the painted chopsticks would contact oily food, 3 oil-based simulants including corn oil, isooctane and 95% (volume fraction, the same below) ethanol solution were selected to conduct migration test at conditions of 2 h of migration time and 70 ℃ of migration temperature according to the requirements from GB 31604.1-2015 and GB 5009.156-2016. The corn oil simulant (5.0 g) obtained by migration test was added into a 20 mL-headspace bottle, and 50 μL of methanol was added. The mixed solution was balanced at 120 ℃ for 30 min. The released gases were entered into gas chromatography-mass spectrometer, and then 28 organic compounds were separated by column heating program using DB-624 capillary column (60 m×0.32 mm, 1.8 μm), and detected with selective ion monitoring mode. The isooctane simulant (1.0 mL) or 95% ethanol solution simulant (1.0 mL) obtained by migration test was added into a sample bottle, and determined by the same conditions of gas chromatography-mass spectrometry, and the working curves were drawn using the matrix matched mixed standard solution series. It was shown that linear relationships between the values of mass fraction and peak area of the detected targets in the 3 matrixes of oil-based simulants were kept in the range of 0.01-0.50 mg·kg^-1, with detection limits (3S/N) in the range of 0.51-1.03 μg·kg^-1. Test for recovery was made on the blank oil-based simulants, giving results in the range of 80.1%-120%, and RSDs (n=6) of the determined values ranged from 1.6% to 9.8%. The migration rules of 28 organic compounds in positive painted chopsticks were investigated under different simulants, different migration time and different migration temperatures. The results showed that the migration amounts of the targets were larger in 95% ethanol solution, and the targets migrated easier with the longer migration time and the higher migration temperature. According to the oral carcinogenic risk model and non-carcinogenic risk model published by the Ministry of Environmental Protection, the risk assessment of the migrators in painted chopsticks was carried out. The results showed that at the migration conditions of 95% ethanol solution, 60 ℃ and 10 d, n-butanol, butyl acetate, ethylbenzene, p-/m-xylene, propylene glycol methyl ether acetate, o-xylene and styrene were detected, with migration amounts ranged from 0.018 mg·kg^-1 to 1.453 mg·kg^-1, and the health risk indexes were less than 1, indicating that the exposure of targets migrating to food simulant from painted chopsticks was at low risk level.