4-Nonylphenol (NP) in food-contact materials: Analytical methodology and occurrence

Abstract

Nonylphenol is a recognized environmental contaminant, but it is unclear whether its occurrence in food arises only through environmental pathways or also during the processing or packaging of food, as there are reports that indicate that materials in contact with food such as rubber products and polyvinylchloride wraps can contain nonylphenol. A review of the literature has highlighted the scarcity of robust analytical methodology or data on the occurrence of nonylphenol in packaging materials. This paper describes a methodology for the determination of nonylphenol in a variety of packaging materials, which includes plastics, paper and rubber. The method uses either Soxhlet extraction or dissolution followed by solvent extraction (depending on the material type), followed by purification using adsorption chromatography. Procedures were internally standardized using ¹³C-labelled nonylphenol and the analytes were measured by gas chromatography-mass spectrometry. The method is validated and data relating to quality parameters such as limits of detection, recovery, precision and linearity of measurement are provided. Analysis of a range of 25 food-contact materials found nonylphenol at concentrations of 64–287 µg g⁻¹ in some polystyrene and polyvinylchloride samples. Far lower concentrations (<0.03–1.4 µg g⁻¹) were detected in the other materials. It is possible that occurrence at the higher levels has the potential for migration to food.

Keywords:

• 4-Nonylphenol
• food packaging
• materials
• gas chromatography-mass spectrometry (GC-MS)
• migration
• alkylphenol ethoxylates (APEOs)
• tris(nonylphenyl)phosphite (TNPP)

Acknowledgements

This work was funded by the UK Food Standards Agency (FSA). The views expressed in this paper are those of the authors and do not necessarily represent those of the FSA, DEFRA or any other organization.