On June 6, 2018, the EU Reference Laboratory for Food Contact Materials (EURL-FCM) of the European Commission’s (EC) Joint Research Centre (JRC) informed about a new study on an analytical method for determining the migration of fluorescent whitening agents (FWA) from plastic beverage cups. The study was published in the peer-reviewed journal Food Additives & Contaminants: Part A on May 30, 2018, and conducted by EURL-FCM researcher João Filipe Alberto Lopes and colleagues.
The researchers developed and validated a high-performance liquid chromatography (HPLC) method with fluorescence detection (FLD) for quantifying six FWAs in plastic beverage cups after their migration into food simulants. The FWAs were: 1) 1,4-bis-(2-benzoxazolyl)-naphthalene (CAS 5089–22-5), 2) 1,2-bis (5-methyl-2-benzoxazole) ethylene (CAS 1041–00-5), 3) 4,4ʹ-bis (2-benzoxazolyl) stilbene (CAS 1533–45-5), 4) 2,5-bis(5-tert-butyl-2-benzoxazolyl) thiophene (CAS 7128–64-5), 5) 4-(2-benzoxazolyl)-4ʹ-(5-methyl-2-benzoxazolyl) stilbene (CAS 5242–49-9), and 6) 4,4ʹ-bis (5-methyl-2-benzoxazolyl) stilbene (CAS 2397–00-4). The limits of detection (LODs) of the developed method ranged from 0.053 to 0.251 μg/kg and the limits of quantification (LOQs) from 0.107 to 0.504 μg/kg. Recoveries were greater than 82% and the relative standard deviations (RSD) below 16%. The expanded combined uncertainty was below 23% for the measurements of all studied FWAs.
Migration tests were performed for ten different plastic cups (three made of polypropylene (PP), one made of recycled polyethylene terephthalate (PET), six made of polystyrene (PS)) according to Regulation (EU) No 10/2011 at 70° C for two hours (‘worst foreseeable use’). The migration experiments showed that the studied FWAs could potentially migrate under the selected conditions, with most pronounced effects for food simulant 50% w/v ethanol in water. “The analytical method proved to be a simple, fast, sensitive and reliable tool for the simultaneous quantification of six of the most used FWAs in both FCM extracts and food simulants after migration experiments,” the researchers concluded.
Alberto Lopes, J.F., et al. (2018). “Development and validation of an HPLC method with fluorescence detection for the determination of fluorescent whitening agents migrating from plastic beverage cups.” Food Additives & Contaminants: Part A (published online May 30, 2018).