Simultaneous Determination of Migration Amount of Acetaldehyde and Vinyl Propionate in Polyethylene Terephthalate Bottle by Headspace-Gas Chromatography

A method was established for simultaneous determination of the migration amount of acetaldehyde and vinyl propionate from polyethylene terephthalate (PET) bottle to food simulants by headspace-gas chromatography. Food simulants of water, 4% (volume fraction, the same below) acetic acid solution or olive oil was poured into a PET bottle, and tests for migration were made at migration temperatures of 40, 60℃ for 1, 10, 20, 30 d. 10 mL of the simulant was taken into a 22 mL sample bottle for headspace to extract target at the headspace equilibrium temperature of 80℃ for 60 min. The vaporized sample was separated by SH-RT-Q-BOND capillary chromatographic column under programmed temperature, and determined by hydrogen flame ionization detector. Three food simulants were used to prepare a series of mixed standard solutions. The results showed that linearity relationships between mass concentrations of acetaldehyde and vinyl propionate and their corresponding peak areas were kept same in the range of 0.5-10.0 mg·L^-1, with detection limits (3S/N) in the ranges of 0.016-0.050 mg·L^-1 and 0.002-0.050 mg·L^-1, respectively; the spiked recovery test was made on the actual samples at the 3 concentration levels, giving recoveries of acetaldehyde and vinyl propionate in the ranges of 96.0%-106% and 94.0%-107%, and RSDs of the measured values (n=6) were found in the ranges of 1.4%-5.3% and 1.9%-5.2%, respectively. The proposed method was used for the analysis of the actual samples, and no vinyl propionate was detected, the migration amount of acetaldehyde in water was greater than that in 4% acetic acid solution and olive oil, and the migration amount at 60℃ was greater than that at 40℃, with the maximum migration amount of acetaldehyde of 4.4 mg·L^-1, lower than the limit (6.0 mg·kg^-1) specified in the national standard of GB 9685-2016.