Screening method for rapid determination of polychlorinated biphenyls in transformer oil by liquid-liquid extraction and gas chromatography-mass spectrometry

• Autor(a) principal: Toledo,Carla
• Data de Publicação: 2007
• Outros Autores: Valle,Luis, Narváez,Jessica, Richter,Pablo
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Journal of the Brazilian Chemical Society (Online)
• Texto Completo: http://old.scielo.br/scielo.php?script=sci_arttext&pid=S0103-50532007000500010
• topic: PCBs; oil transformer; liquid-liquid extraction; GC-MS

A rapid and simple method was developed for screening polychlorinated biphenyls in transformer oil. The method is based on liquid-liquid extraction in methanol and subsequent direct gas chromatography-mass spectrometric determination. The extent of methanol polarity allows to extract the PCBs, co-extracting a minimum amount of the apolar oil components, thus avoiding the time-consuming steps involving in sample preparation. Since the regulation established internationally for wastes containing PCBs is 50 mg kg-1, the method rapidly determines whether the transformer oil is PCBs-contaminated or not. In order to reach the best conditions for extraction a multivariate optimization was carried out considering two significant variables: volume of methanol and extraction time. Under optimum conditions, recoveries of Aroclor 1256 and Aroclor 1260 were between 80 and 100%, and precision, expressed as relative standard deviation, was from 2 to 4%. The method was applied to real samples polluted with PCBs.