Determination of Residual α-Methylstyrene in Styrene-based Polymer Products and Migration of α-Methylstyrene into Food-simulating Solvents

Abstract

Residual α-methylstyrene (α-MSt) in products made of styrene (St)-based polymers, such as polystyrene (PS), St-acrylonitrile copolymers (SAN) and acrylonitrile-butadiene-St resins (ABS), was determined by gas liquid chromatography. St-based polymers were dissolved in dichloromethane and analyzed for α-MSt by direct injection of the polymer solutions. Further, α-MSt migrations from ABS sheet to water, 4% aceteic acid, 20% ethanol and n-heptane were measured by mass fragmentography, using selected ion recording at m/e 118, 117 and 103.In commercial PS and SAN products, α-MSt was not detected at a quantitation limit of 20ppm, but in ABS products such as ladles, graters, sheets and lunch trays, residual α-MSt amounted to 72-2496ppm, α-MSt migration from 2 commercial ABS sheets into 3 food simulants (water, 4% acetic acid and 20% ethanol) was not detected. However, some migration into n-heptane was detected, so α-MSt appears to have some tendency to migrate into oils and fats and fatty foods.