Migration studies from paper and board food packaging materials. 1. Compositional analysis.

A survey of 32 paper and board materials intended for food contact has been undertaken. Sample composition was analysed to identify chemicals with a potential to migrate to foods. Representative materials covering a range of uses such as aqueous and fatty foods, and use at ambient and elevated temperatures, were obtained from industry. The samples were examined in their unfinished state, even where the final form would have included lamination to plastics, printing, or other treatments. A comprehensive and systematic analytical approach was applied which included determination of volatiles by headspace GC-MS, extraction using water, ethanol and chloroform with subsequent analysis by GC-MS and HPLC, and multi-element screening by ICP-MS. The solvent extracts were also weighed to determine the total amount of material available for migration. A large number of volatile substances were identified with alkyl and aryl aldehydes predominating in the majority of samples. Substances identified in solvent extracts included 2,6-di-tert-butyl-4-hydroxytoluene (BHT), di-tert-butylphenol, benzophenone, 4,4'-bis(dimethyl amino) benzophenone (Michler's ketone), triphenyl methane, bicyclohexylphenylphenanthrene carboxylic acid (and its methyl ester) and abietic acid. Levels of these substances were however generally below 1 mg/kg paper. Of the inorganic elements, arsenic and mercury were not detected above the limits of determination of 1.8 and 0.4 mg/kg respectively in any of the 10 samples examined. Cadmium was detected in teabag tissue and in unbleached Kraft paper at 0.3 mg/kg. Chromium was present in seven samples at 1.1-7.8 mg/kg, whilst lead was present in nine of the 10 samples at levels ranging from 0.3 to 5.9 mg/kg.

4,5-Dimethylthiazole-N-oxide-S-oxide: a metabolite of chlormethiazole in man.

The metabolic fate of chlormethiazole in healthy male subjects has been investigated following the oral administration of a single dose of chlormethiazole edisylate. Five urinary C-oxidation metabolites were identified and shown to be identical with previously reported metabolites. A novel metabolite, of molecular formula C5H7NO2S, was shown by trimethylsilylation, deuterium exchange, reduction studies and by its i.r., n.m.r. and mass spectrum, to be 4,5-dimethylthiazole-N-oxide-S-oxide. This is the first reported metabolite which involves the oxidation of the two heterocyclic atoms in aromatic rings. The formation and thermal stability of the compound is ascribed to resonance stabilization.