In their publication “LC-MS/MS analytical procedure to quantify tris(nonylphenyl)phosphite, as a source of the endocrine disruptors 4-nonylphenol in food packaging materials” appearing in the peer-reviewed scientific journal Food Additives & Contaminants: Part A, Nestlé researchers Pascal Mottier and colleagues describe a new method for ensuring food contact material (FCM) safety (Mottier et al. 2014). Nonylphenol, a known endocrine disrupting chemical (EDC), is a degradation product of the antioxidant additive tris(nonylphenyl)phosphite (TNPP) and therefore a non-intentionally added substance (NIAS). In plastics, TNPP reacts with peroxide radicals, thereby reducing polymer degradation. During this chemical process, TNPP itself is degraded into nonylphenol which can migrate out of the plastic and thus contaminate food. In their new study, Mottier and colleagues describe a novel approach to analyzing TNPP contents of multilayer plastic laminates, as well as subsequent detection of its breakdown product nonylphenol in packaging extracts. The new method permits discrimination between nonylphenol from TNPP degradation, and other sources (like direct food contamination).
Analysed materials consisted of typical multilayer laminates made from micron-thin layers of PET/Aluminum/PET/PE and PET/Aluminum/Nylon/PE (PET: polyethylene terephthalate, PE: polyethylene). Extracts were prepared using hexane-acetone mixtures and analysed using liquid chromatography-tandem mass spectrometry (LC-MS/MS).
Nonylphenol is a Substance of Very High Concern (SVHC) under REACH. As such, the European Chemical Agency (ECHA) will reevaluate nonylphenol in 2014 according to its schedule. Under the European regulation for food contact plastics (EC 10/2011 (pdf)), the use of a TNPP containing mixture (“phosphorous acid, tris(nonyl-and/or dinonylphenyl) ester”) as additive is authorized, with a specific migration limit set at 15 mg/kg food. Other substances that can degrade into nonylphenol are used in paper and board FCMs (ethoxylated nonylphenol, CAS Nr. 9016-45-9 and CAS Nr. 26027-38-3, EFSA 2011). In the US, TNPP is cleared as an indirect food additive.
Reference
Mottier, P. et al. (2014). “LC-MS/MS analytical procedure to quantify tris(nonylphenyl)phosphite, as a source of the endocrine disruptors 4-nonylphenols, in food packaging materials.” Food Additives & Contaminants: Part A (online February 19, 2014).
