Development of a method for extraction of organochlorine pesticides from rendered chicken fat via supercritical fluoroform

Quantitative recoveries relative to liquid-solid extraction of organochlorine pesticides (OCPs) from rendered chicken fat were obtained using pure fluoroform as an extraction fluid. No cleanup procedure of the extract was employed prior to analysis via gas chromatography/electron capture detection (GC/ECD). Extraction of OCPs from rendered chicken fat was also performed with methanol-modified fluoroform. However, coextracted fat components were trapped along with the OCPs such that the GC/ECD trace of the extract showed a high background level which caused quantification to be less reliable. While no cleanup step nor activated alumina to retain fat in the extraction vessel was necessary, it was demonstrated that a longer extraction time was required to extract OCPs from fat using pure fluoroform than with methanol-modified fluoroform. Since little or no fat was extracted by fluoroform, the longer extraction time is believed to be caused by partitioning of OCPs between unextracted fat and fluoroform.