Interactions eau-matières plastiques souples : identification des composés organiques par couplage Chromatographie en phase gazeuse-spectométrie de masse

Water-floppy plastic materials: identification of organic compounds by gas-chromatography-mass spectrometry

¹ Majorité générale, Laboratoire de Chimie Analytique, B.P. 61, 83800 Toulon Naval
² Laboratoire d'Hygiène et de Recherche en Santé Publique (LHRSP) Université de Nancy, 11, rue Gabriel-Péri, 54515 Vandœuvre-lès-Nancy
³ Laboratoire de Spectrométrie de Masse et Chimie Laser Institut de Physique et d'Électronique de Metz, Technopôle 2000 1, boulevard Arago, 57078 Metz Cédex 03

Résumé

Une étude de conservation d'eau du réseau aseptisée en sachets plastiques souples a été effectuée pendant un an à différentes températures. Après extraction liquide-liquide par le dichlorométhane, les composés organiques en solution ont été identifiés par CG/SM.

Des micropolluants organiques apparaissent régulièrement dans la plupart des échantillons: ce sont essentiellement des dérivés d'antioxydants phénoliques, additifs de fabrication de matières plastiques, des dérivés aliphatiques et phtaliques.

Ces résultats montrent que de nombreuses migrations d'additifs de plastiques non volatils se produisent à partir du matériau vers l'eau.

Abstract

A study concerning conservation of asepticized tap water in three different floppy plastic bags named X, Y and Z, has been driven during a full year, at several different temperatures. (20, 37 and 55 °C) with the purpose of possibly constituting some water reserves for military personnel or populations in distress. After a liquid-liquid extraction by methylchloride, the organic compounds in solution, were identified by gas Chromatography/Mass Spectrometry (GC/MS).

During the tests, several organic micropollutants oftenly appeared: they actually are phenolic antioxydants derivatives, - such as IRGAFOS 168 and IRGANOX 1010 - as well as additives for manufactured plastics, aliphatic and phtalic derivatives.

Most of the compounds - of which toxicity is not mentioned - remain present and stable during the experiment, but in varying concentrations for the three types of bags.

The most important quantities found in the water are in order of 80 and 200 µg/l for two compounds (1,2 - epoxy -3- methylhexane and bis(2- methoxyethyl) phtalate) the others being between 0.1 and 20 µg/l.

The quantities found are very far from the global migration limits (MG), fixed dy the directive 90/128/EEC (max. 60 mg/kg of food).

Those results show that many migrations of non volatil plastics additives may occur between material and water; stemming from these initial compounds, some transformations in oxydation by products have been observed.

The conclusions allow to stress out the necessity of migration laboratory tests in the legal context of plastics employ autorisations, especially those concerning food packaging and all the more because of long conservation time.