A03031 and A03032: Development of multi-methods for determining the migration of antioxidants and stabilisers included in Directive 2002/72/EC

Study Duration: May 2001 to October 2004

Contractor: Rapra Technology Ltd and TNO

Food-contact packaging, food storage containers and articles used in the preparation of food are commonly made from many different types of plastic materials. Various substances are added to the plastic before processing to assist with the production. For example, to prevent thermal and oxidative degradation of the plastic during processing and in subsequent service.

The current European Directive relating to plastic materials and articles intended to come into contact with foodstuffs is Commission Directive 2002/72/EC as amended. This Directive lists monomers and starting substances, including antioxidants and stabilisers, that may be used safely in the production of plastics. For some of these permitted chemicals the Directive protects the safety of consumers by setting restrictions – known as specific migration limits (SMLs) – on how much may transfer to foodstuffs, or test simulants (solvents).

The aim of this project was to develop analytical methods (multiple analyte methods) for the detection and quantification of antioxidants and stabilisers included in the food-contact plastics Directive at or below their specific migration limits. The research has been undertaken jointly between Rapra Technology Ltd, Shawbury, UK and TNO, The Netherlands.

The specific antioxidants and stabilisers examined in the research have included:

• hindered phenol antioxidants
• other phenolics
• phosphite and phosphonites
• thioester and other sulphur containing non- phenolic stabilisers
• polymeric hindered amine light stabilisers (HALS)
• UV absorbers
• organotin stabilisers

A review was undertaken of published methods and experimental investigations for the antioxidants and stabilisers of interest. In-house studies and also an extensive study sponsored by the European Commission that examined the stability of a range of plastic additives in food simulants were included in the review.

Based on this review, combined liquid chromatography/mass spectrometry (LC-MS) was selected as the technique of choice except for the organotin class of compounds. A derivitisation and combined gas chromatography/mass spectrometry (GC-MS) method was chosen for these compounds.

Reference mass spectra for most of the antioxidants and non-tin stabilisers listed in Directive 2002/72/EC have been recorded. A liquid chromatography mass spectrometry (LC-MS) method has been developed for selected antioxidants, non-tin stabilisers and ultra violet (UV) absorbers.

The LC-MS methodology developed has enabled the specific identification and quantification of substances with low specific migration limits directly in food simulants, including the fatty food simulant olive oil, without the necessity to undertake extraction and clean-up of the oil prior to analysis. However, the purity of mobile phase solvents, and the level of contamination of the ion source and MS detection system affected the performance of the LC-MS instrument and needed to be tightly controlled to achieve reproducible data. The method was not suitable for the detection of the polymeric hindered amine light stabilisers (HALS) or those antioxidants that decompose in food simulants.

Migration of antioxidants and stabilisers from some test samples has been examined. In all cases, levels of migration were low and well within the specific migration limit (SML) value for each antioxidant examined.

A gas chromatography mass spectrometry (GC-MS) method has been developed and validated for a range of organotin stabilisers. Using this method, migration of tin stabilisers was not detected from standard PVC materials into the food simulants water, 3% acetic acid, 15% ethanol and olive oil. The detection limit for all substances and simulants was well below the specific migration limit set in Directive 2002/72/EC. Similarly, migration of tin stabilisers was not detected from a small selection of food market PVC materials into the food simulant olive oil. The test conditions applied were 30 days at 40°C.

This work provides useful groundwork for the development of fully validated, robust analytical techniques for the determination of antioxidants and stabilisers. Further work is required but it is anticipated that both will be taken forward for submission to the European Standards Body CEN for consideration as new European standard methods for examining the regulatory compliance of food-contact plastics.

Final report is available from the FSA Library and Information centre. To obtain a copy, please contact the Enquiry Desk, Dr Elsie Widdowson Library and Information Services, Food Standards Agency ( tel: 020 7276 8181/8182 or email: library&info@foodstandards.gsi.gov.uk ).

Contact: For any enquiries concerning this research project, please contact the relevant programme contact or email: science@foodstandards.gsi.gov.uk