Fluorescence based passive samplers for diluted bitumen in water
Passive samplers are low-cost and simple devices that can be used to monitor analytes in dynamic systems. In this project, Polydimethylsiloxane and UltraEverDry films were tested for application as passive samplers for dilbit. Three types of oil were used, dissolved, mechanically dispersed, and mechanically dispersed with chemical enhancement. PDMS absorbed oil, with dispersed oil allowing for faster uptake into PDMS than dissolved oil. Equilibration times ranged from 4-8 days for dispersed oil, depending on the thickness of the film. The lower detection limit of the thick PDMS films is approximately 0.4 ppm but can be improved by improving film reproducibility. Thin films had a partition coefficient of approximately 1000 while thick films had a partition coefficient of apprxoximately 6000. Oil can be extracted from PDMS films with ethanol giving a volume dependent signal. Films and ethanol extracts can be used to monitor the concentration of dilbit present in model systems for riverbeds and real-life oil release scenarios. Oil was not observed adsorbed to UltraEverDry.