Lipid Extraction and Determination of Halogenated Phenols and Alkylphenols as Their Pentafluorobenzoyl Derivatives in Marine Organisms

Abstract

A method was developed for the extraction of lipids and analysis of halogenated phenols and alkylphenols in marine organisms. The extraction efficiency was evaluated by comparing the extractable lipid content and the recovery of 13 added phenols from three different marine species (herring, cod, and blue mussel), with the corresponding results from three well-established extraction procedures, the Bligh and Dyer (B&D), the Smedes (S), and the Jensen (J) methods. The J method and the new method, Jensen centrifugation (Jc), gave phenol recoveries of 80-100% for all species, whereas the B&D and S methods gave relatively low recoveries for the most acidic phenols, with recoveries of only 20-50% for pentachlorophenol (PCP) depending on the species. It was concluded that this effect was governed by the dissociation of the phenols and adsorption to the protein tissue during the extraction (due to ionic interactions). To increase the sensitivity of the analysis, the phenols were converted to their pentafluorobenzoyl esters, by using a tetrabutylammonium-catalyzed extractive acylation. The reaction was quantitative within 2 min at room temperature, and the formed derivatives were persistent enough to withstand treatment with concentrated sulfuric acid.