Passive equilibrium sampling of hydrophobic organic compounds in homogenised fish tissues of low lipid content

Passive equilibrium sampling using polymer samplers in lean tissue is one of the current challenges in assessing bioaccumulation and biomagnification due to the long time needed to reach equilibrium. Despite recent progress achieved by rolling pieces of intact fish fillet with sheets of silicone, there is still a need for a passive sampling method for homogenates that achieves equilibrium before tissue decay starts. In this work, a new approach for relocation of silicone passive samplers in homogenates of lean fish was established for three homogenates with lipid contents varying from 1.2% to 6.1%. Results showed that for 20 model hydrophobic organic compounds with log K_OW between 3.9 and 7.8, equilibrium between the silicone and the tissue was achieved in less than 3 days at 4 °C. The concentrations in lipids obtained using passive equilibrium sampling and those from traditional total solvent extraction agreed well, within a factor of 1.3. This new procedure extends the use of passive samplers to homogenised fish tissues of low lipid content, which is highly relevant for environmental studies focused on bioaccumulation of contaminants.