Comparison of migration from polyethersulphone and polycarbonate baby bottles

This work presents two analytical methods developed for measuring three components of polyethersulphone (PES) and applying them to the migration testing of 30 baby bottles made of PES. The study also provides migration results under the same conditions for bisphenol A (BPA) from 40 polycarbonate baby bottles using a well-established method adapted to low concentrations. For PES bottles, migration of diphenyl sulphone (DPS), 4,4'-dichlorodiphenyl sulphone (DCPS) and 4,4'-dihydroxydiphenyl sulphone (DHPS; also known as bisphenol S) was carried out using two different analytical methods with detection limits of 0.1-0.3 μg/kg, and, therefore, much below their respective European Commission Directive 2002/72/EC legislative migration limits of 50-3000 μg/kg, respectively. In parallel, 40 bottles made of polycarbonate were analysed for the migration of BPA using a method validated at EU level and modified to give a lower detection limit of 0.1 μg/kg. Migration tests were conducted into the simulant for milk 50% EtOH (as per Commission Regulation No. 321/2011 of 1 April 2011) according to the test conditions from the guidelines on test conditions for articles in contact with foodstuffs (with a focus on kitchenware) prepared by the EU Reference Laboratory and its network of National Reference Laboratories. None of the 30 bottles made of PES released any detectable amounts of DCPS or DHPS and only two bottles released a very low amount of DPS of ~1 μg/kg in the milk food simulant compared to a regulatory limit of 3000 μg/kg. For PC bottles, 32 bottles of 40 (80%) did not release BPA above the LOD of 0.1 μg/kg (in any of the three migration tests performed on each bottle). The other 20% of bottles exhibited only very minor migration, where the highest level in the first migration test was 1.83 μg/kg and most bottles did not release detectable BPA in the second and third test. Only one bottle, with a migration level of 1.08 μg/kg, in the first test still showed a detectable level in the last migration test (i.e. 0.42 μg/kg). It is important to note that the legal limit (European Commission Directive 2002/72/EC) was still 600 μg/kg for polycarbonate bottles at the time of purchase, preceding the precautionary ban taking effect from 1 June 2011 (Commission Directive 2011/8/EU; Commission Regulation No. 321/2011). This confirms that the likelihood of migration of BPA is very low and remains at very minute amounts. The results also suggest the absence of release from PES bottles based on the set of bottles investigated.