Testing for compliance with migration limits: Determination of 1,2-, 1,3-, and 1,4-dihydroxybenzenes in food-simulating solvents by liquid chromatography

A method, intended for regulatory purposes, for quantitative determination of the plastics monomers 1,2-, 1,3-, and 1,4-dihydroxybenzene in food- simulating solvents is described. Liquid chromatography is used with UV detection and 2-methyl- 1,3-dihydroxybenzene as internal standard. Repeatability, stability, and migration tests were conducted. The limits of detection were in the range 0.03-0.40 mg/kg for the 3 phenols in aqueous and fatty food simulants. Relative repeatability standard deviations at migration limits of 6, 2.4, and 0.6 mg/kg for 1,2-, 1,3-, and 1,4-dihydroxybenzene, respectively, ranged from 0.8 to 4.8% for the food simulants tested. A commercial sample of polyetherketone made from 1,4-dihydroxybenzene was tested with the method. No polymer-derived interferences were found. The method is thus suitable for testing against migration limits for the 3 monomers.