Polymer selection for passive sampling: a comparison of critical properties

Area of Science:

• Environmental Chemistry
• Polymer Science
• Analytical Chemistry

Background:

• Single-phase passive samplers are increasingly used for hydrophobic contaminant monitoring, complementing bi-phasic semipermeable membrane devices (SPMDs).
• Selecting appropriate polymers is crucial for effective passive sampling, influencing accuracy and reliability.

Purpose of the Study:

• To evaluate critical properties of 13 polymers for passive sampling applications.
• To compare polymers based on oligomer release, solvent swelling, diffusion, and partition coefficients for target contaminants.

Main Methods:

• Tested polymers included low-density polyethylene (LDPE), polyoxymethylene (POM), silicone rubbers (SRs), and ethylene/octene co-polymer (EXACT).
• Evaluated oligomer release, swelling in various solvents, diffusion coefficients, and partition coefficients for polycyclic aromatic hydrocarbons (PAHs).

Main Results:

• Silicone rubbers (SRs) and LDPE exhibited 2-4% oligomer release, while EXACT showed ~1%, and POM had no detectable release.
• Diffusion coefficients were highest in SRs, followed by LDPE and EXACT; POM showed no measurable diffusion within 24 hours.
• Polymer-water partition coefficients varied significantly, with POM having the lowest and LDPE/EXACT the highest values.

Conclusions:

• Silicone rubbers (SRs) offer lower transport resistance compared to LDPE and EXACT for passive sampling of hydrophobic contaminants.
• Polyoxymethylene (POM) demonstrates minimal oligomer release and diffusion, suggesting potential for specific applications, but also low partitioning.
• Polymer selection significantly impacts passive sampling performance, necessitating careful consideration of oligomer release, diffusion, and partitioning properties.