Determination of Residual Monomers and Solvents in Styrene-acrylonitrile Copolymers and Rubber Modified Resins and Their Products Used as Food Packaging Materials

Head-space-GC was applied to the determination of 5 residual monomers and solvents, i.e., 1,3-butadiene, acrylonitrile, styrene, toluene and ethylbenzene, in styrene-acrylonitrile copolymers and rubber modified resins, as well as in their products used as food packaging materials. The sample (1.00 g in form of granules or slices) was treated in a sealed 20 mL head-space bottle with 3 mL of DMF, and the solution was introduced into the instrument and analyzed as the prescribed conditions, DB-WAX capillary column was used for separation under programmed temperature elevation from 50 ℃ to 180 ℃, and FID was used for determination. Lower limits of determination (10S/N) of the method were found in the range of 0.036-3.8 mg·kg-1 for the 5 compounds. Values of recovery found by standard addition were ranged from 90.8% to 98.0% with RSD′s (n=6) less than 3%. Four samples each of the AS and ABS plastics were analyzed by the proposed method, as shown by the experimental results, besides limited amounts of acrylonitrile, definite amounts of toluene and ethylbenzene as well as relatively high contents of styrene were also found, which were hiddeen dangers against food safety.