Possibilities and limitations of equilibrium sampling using polydimethylsiloxane in fish tissue

Area of Science:

• Environmental Chemistry
• Analytical Chemistry
• Ecotoxicology

Background:

• Polydimethylsiloxane (PDMS) is established for passive equilibrium sampling in abiotic environments.
• Extending PDMS sampling to biological tissues, particularly lipid-rich ones, presents new opportunities for contaminant analysis.

Purpose of the Study:

• To investigate the feasibility and constraints of using PDMS thin-film extraction for in-tissue equilibrium sampling.
• To assess the method's performance across fish species with diverse lipid content.
• To evaluate the sampling of lipophilic organic pollutants, using polychlorinated biphenyls (PCBs) as model compounds.

Main Methods:

• PDMS thin-films were inserted into intact fish tissues for durations ranging from 1 hour to 1 week.
• Thin-films were subsequently solvent-extracted and analyzed via gas chromatography-mass spectrometry.
• Equilibration was assessed using multiple PDMS film thicknesses and time-series kinetic analysis.

Main Results:

• Rapid equilibration (within hours) was observed in lipid-rich fish tissues.
• Equilibrium was not achieved within a one-week sampling period in fish tissues containing low to medium lipid content (≤2%).
• The method demonstrated sufficient sensitivity for determining PCB equilibrium partitioning concentrations in Baltic Sea lipid-rich fish samples.

Conclusions:

• PDMS thin-film extraction is a viable and rapid technique for in-tissue equilibrium sampling of lipophilic contaminants in fatty fish.
• The method's effectiveness is dependent on tissue lipid content, with limitations in low-to-medium lipid tissues.
• This approach shows promise for analyzing contaminants in various fatty biological tissues.