Determination of dihydroxybenzenes in plastic food packaging materials andin food simulating liquids using capillary electrophoresis

A capillary electrophoresis method has been developed to determine 1,2-dihy droxybenzene and 1,3-dihydroxybenzene in the food simulants distilled water , 3% acetic acid, 15% ethanol, and olive oil. Both substances, used as mono mers and additives to make food packaging plastics, could be analyzed withi n 15 min. The 1,4-dihydroxybenzene isomer was unretained and eluted with th e electroosmotic flow and so the CE method can give only a semi-quantitativ e estimate of this isomer if it is present as a migrant. The analytical rec overy for the 1,2- and 1,3-isomers from spiked simulants was good at 87% to 98% except for 1,2-dihydroxybenzene which could only be recovered to the e xtent of 58% from olive oil. Calibration graphs were linear and the limit o f detection for each substance was 0.6 mg/kg, which is well below migration limits for these substances. It is concluded that CE offers a rapid and re liable analysis for the control of migration from plastics intended for foo d contact which employ 1,2-dihydroxybenzene or 1,3-dihydroxybenzene during manufacture, and offers a screening method for 1,4-dihydroxybenzene migrati on.