Chemometric tools to highlight non-intentionally added substances (NIAS) in polyethylene terephthalate (PET) Amine Kassouf a,b,c , Jacqueline Maalouly a , Hanna Chebib a , Douglas N. Rutledge c , Violette Ducruet b,n a ER004 “Lebanese Food Packaging”, Faculty of Sciences II, Lebanese University, 90656 Jdeideth El Matn, Fanar, Lebanon b INRA, UMR 1145 Ingénierie Procédés Aliments,1 Avenue des Olympiades, 91300 Massy, France c AgroParisTech, UMR 1145 Ingénierie Procédés Aliments,16 rue Claude Bernard, 75005 Paris, France article info Article history: Received 19 February 2013 Received in revised form 13 June 2013 Accepted 17 June 2013 Available online 4 July 2013 Keywords: PET NIAS HS–SPME/GC–MS Principal Components Analysis (PCA) Independent Components Analysis (ICA) Common Components and Specific Weights Analysis (CCSWA) abstract In an effort to identify non-intentionally added substances (NIAS), which is still a challenging task for analytical chemists, PET pellets, preforms and bottles were analyzed by an optimized headspace solid phase microextraction coupled to gas chromatography–mass spectrometry (HS–SPME/GC–MS). Finger- prints obtained by the proposed method were analyzed by three chemometric tools: Principal Components Analysis (PCA), Independent Components Analysis (ICA) and a multi-block method (Common Components and Specific Weights Analysis CCSWA) in order to extract pertinent variations in NIAS concentrations. Total ion current (TIC) chromatograms were used for PCA and ICA while extracted ion chromatograms (EIC) were used for CCSWA, each ion corresponding to a block. PCA managed to discriminate pellets and preforms from bottles due to several NIAS. Volatiles like 2-methyl-1,3-dioxolane, ethylene glycol, ethylbenzene and xylene were responsible for the discrimination of pellets and preforms. Less volatile compounds like linear aldehydes and phthalates were responsible for the discrimination of bottles. ICA showed more specific discriminations especially for bottles and pellets while CCSWA managed to discriminate preforms. The proposed methodology, combining HS–SPME/GC– MS with chemometric tools proved its efficiency in highlighting NIAS in PET samples in a relatively simple and fast approach compared to classical techniques. & 2013 Elsevier B.V. All rights reserved. 1. Introduction Polyethylene terephthalate (PET) has become the most widely used packaging material world-wide for beverages, replacing other packaging materials such as PVC, glass and metal. The reason for this development is the excellent properties of PET which is lightweight, shatter resistant, transparent, and recyclable [1]. Nowadays, PET bottles are used for soft drinks, mineral waters, energy drinks, vegetable oils and ice teas as well as for more sensitive beverages like beer, wine and fruit juices [2]. In recent years, concerns about the safety of packaged foods have increased noticeably. Those worries are related to the leach- ing of chemicals from packaging material into the packaged food. In fact, plastic packaging contains many additives such as anti- oxidants, stabilizers, lubricants, colorants, anti-statics and many other processing aids which may migrate into the packaged food. Yet, all these substances, intentionally added to the polymer, are well known and documented in the European commission regulation EU 10/2011 [3] on plastic materials intended to come into contact with food. This regulation establishes a positive list of those compounds authorized for use in plastic formulations and manufacturing and provides migration limits for quite a number of molecules. However, concerns are rising nowadays about unknown sub- stances called “non-intentionally added substances” or NIAS [4]. This category of molecules is defined by the same regulation as “impurities in the substance used or reaction intermediates formed during the production process or decomposition or reac- tion products”. This new EU regulation [3] gives much importance to NIAS and specifies that “the notion of risk due to the substance, concerns not only the substance itself but also the impurities in this substance and any reaction or degradation product”, putting emphasis on the gravity of the problem caused by the appearance of NIAS in food packaging materials. NIAS in PET have many origins. The first is impurities in the substances used in the manufacture of PET. In this case, the investigation may be difficult due to the potentially hazardous character of the contamination. These impurities may be intro- duced along with additives and colorants master-batches, with solvents, catalysts, polymerization and production aids, etc. Contents lists available at SciVerse ScienceDirect journal homepage: www.elsevier.com/locate/talanta Talanta 0039-9140/$ - see front matter & 2013 Elsevier B.V. All rights reserved. http://dx.doi.org/10.1016/j.talanta.2013.06.029 n Corresponding author. Tel.: +33 169935047; fax: +33 169935044. E-mail address: violette.ducruet@agroparistech.fr (V. Ducruet). Talanta 115 (2013) 928–937