Investigating the use of deuterodiazomethane derivatization for enhancing trace gas chromatography/mass spectrometry determination of halophenols in the presence of haloanisoles

Abstract

The trace detection of halophenols and haloanisoles by means of single, low-resolution GC/MS analysis, following stable isotope derivatization, is described. Halophenols (principally pentachlorophenol and 2,4,6-tribromophenol) are used as wood preservatives. If wood treated with these materials is used to manufacture food packaging, the food may become contaminated. The halophenols, which impart a 'chemical/medicinal' taint, can be converted to their corresponding anisoles by microbial action and these compounds may have much lower, 'musty/mouldy' taint thresholds (ng/L-pg/L concentration in water). Because of their greater polarity, tri-, tetra- and penta-chlorophenols are transmitted less efficiently through a GC column than are their less chlorinated homologues or the haloanisoles. In order to determine both halophenols and haloanisoles with high sensitivity it is therefore necessary to derivatize the halophenols. Methylation with diazomethane is generally preferred because of its convenience and the ease of identification of the products. The use of isotopically labelled diazomethane (CD2N2) permits derivatized halophensols to be distinguished from native haloanisoles. The successful application of this approach to the analysis of cardboard packaging material with a musty odour is described.