Development of a method for the analysis of polybromo biphenyls and bifenyl oxides in plastics
Ontwikkeling van een methode voor de bepaling van polybroombifenylen en bifenyloxiden in kunststoffen
de Jong APJM, Koers-Jacquemijns M
RIVM Report 679101024
This report describes the development of a method for the analysis of polybromo biphenyls and bifenyl oxides (PBBs/PBBOs) in plastics. The method will be used for regulatory purposes on the possible future banning of these compounds. Investigations were mainly focused on the liberation of these compounds from the solid samples. Analysis was performed by the proposed method of choice, gas chromatography-electron capture detection (GC-ECD). For this purpose the materials of interest were divided into solvable and non-solvable materials. For solvable material, analytes were quantitatively liberated from the matrix simply by dissolvation of the material. For non-solvable materials, reflux extraction in toluene using the Soxhlet method was studied and tested on low density polyetylene (LDPE). Critical parameters for this method are the duration of extraction and the corresponding yield. For LDPE the extraction time of 2 h was found suitable, with an estimated yield of 75%. In both methods, dissolved polymer did nor cause interferences or other problems during GC-ECD analysis. Precipitation of dissolved polymers can be applied when required. No losses of analytes were observed during this process. Extracts and solutes were highly diluted prior to analysis, viz. to a ratio of 1 part of material into 1.000.000 parts of solvent (ppb). The limit of determination of the method was better than the required level of 1 g PBB/PBBO/kg (0.1 w%). The linearity of the method was limited by the ECD detector to about two orders of magnitude, but can be increased by a further dilution of final extract in proportion to the expected level in the material under investigation. Other performance characteristics of the proposed method could not be determined due to the lack of reference materials. Before implementing in practice, these should be evaluated preferably in an interlaboratory comparison and validation trial. For this purpose and for future use in the laboratories involved, a larger variety of appropriate reference materials known addition levels should be made available.