Four water-based food simulants, i.e. 4% (
φ) acetic acid solution, 10% (
φ, the same below), 20% and 50% ethanol solutions, and one oil-based food simulant (olive oil) were selected as the food simulants. At the end of migration test, the food simulated solutions of the above 5 simulants were obtained, 1.00 mL aliquots were taken from the 4 water-based food simulated solutions and placed separately into 4 headspace flasks, and 1.000 g of the oil-based food simulated solution was taken and placed into the 5th headspace flask. 200 μL of DMF were added to each of the 5 headspace flasks, and after tight capping, the solutions were equilibrated separately with headspace for 15 min at 80℃ (for water-based food simulated solutions) and at 100℃ (for oil-based food simulated solution). The 3 analytes (1-hexene, 1-octene and vinyl acetate) in their gaseous state were introduced into the DB-WAX chromatographic column (60 m×0.25 mm, 0.25 μm) and separated according to their retention times of 5.303, 6.632, 7.402 min respectively. Linearity ranges of the 3 analytes in the above 5 food simulated solutions were found same between 0.5-5.0 mg·kg
-1 for 1-hexene, between 2.5-25.0 mg·kg
-1 for 1-octene and between 2.0-20.0 mg·kg
-1 for vinyl acetate. Their detection limits (3S/N) found were:(for 1-hexene) 0.05 mg·kg
-1 (in water-based food simulants), and 0.2 mg·kg
-1 (in oil-based food simulant); (for 1-octene) 0.05 mg·kg
-1 (in water-based food simulants), and 1.0 mg·kg
-1 (in oil-based food simulant); (for vinyl acetate) 0.5 mg·kg
-1 (in 50% ethanol solution), 0.2 mg·kg
-1 (in the remainder 3 water-based food simulants), and 1.0 mg·kg
-1 (in oil-based food simulant). Recovery was tested by standard addition at 3 concentration levels, giving results of recovery in the range of 88.0%-103% with values of RSDs (
n=5) of determined values in the range of 1.2%-7.9%. Twenty samples of polyethylene food-contacting materials were analyzed by the method. Neither of the 3 analytes was found.
WT5HZ
DownLoad: