Determination of endocrine disrupting compounds and their metabolites in fish bile

Abstract

This work describes a new methodology for the simultaneous determination of a large variety of emerging and persistent organic compounds and some of their metabolites in fish bile samples. The target compounds were musk fragrances, alkyl phenols, hormones, pesticides, phthalate esters and bisphenol-A, all of them with a known endocrine disrupting effect. To achieve the determination these three steps were optimized: i) an enzymatic hydrolysis of the metabolites to render the unconjugated compounds; ii) the solid phase extraction of the target analytes (Plexa cartridges 200-mg); and, iii) a clean-up of the extracts (Florisil cartridges 1-g). The samples were analyzed by gas-chromatography-mass spectrometry (GC-MS), though the polar fraction required a previous derivatization with O-bis (trimethylsilyl) trifluoroacetamide. Good apparent recoveries (63-122%), repeatability (<20%) and limits of detection (LODs) ranging between 0.04 and 459 ng/mL were obtained. This method was applied to the analysis of the target analytes in bile samples of thicklip grey mullets (Chelon labrosus) from five different populations of the Basque Coast (South East Bay of Biscay) during the period of May-June 2012. The target analytes were found at concentrations ranging from <LOD to 19,226 ng/mL and the most polluted site was Gernika. Bioconcentration factors (log BCF) were estimated (range of 1.69-5.55) and BBP and NP mix showed the highest values. A deep discussion has been carried out in order to explain the different concentration levels of the different sampling sites.

Keywords: Bioconcentration factor; Chelon labrosus; Endocrine disrupting compounds; Fish bile; Gas chromatography–mass spectrometry; Solid phase extraction.