Thompson Rivers University

Science Seminar Series—On-line membrane sampling and direct mass spectrometry of trace organic contaminants in complex samples

Dr. Erik Krogh presents On-line membrane sampling and direct mass spectrometry of trace organic contaminants in complex samples as part of the Science Seminar Series.

He is a professor in the department of chemistry at Vancouver Island University.


Recent work in our group has employed the use of semi-permeable membranes to directly measure trace organic compounds of emerging concern (e.g., pharmaceuticals, microcystins) in complex heterogeneous samples.

The presentation will introduce some recent applications with a focus on the analysis of naphthenic acids (NAs) associated with oil sands process waters, which have the potential to be released into aquatic environments with a range of toxic effects on receiving organisms.

Conventional analytical techniques are characterized by extensive processing, resulting from the complexity of the sample and difficulty in distinguishing NAs from naturally occurring dissolved organic matter (DOM).

We report the use of on-line membrane extraction and direct mass spectrometry techniques using a capillary hollow fibre polydimethylsiloxane (PDMS) membrane to yield meaningful qualitative and quantitative information from both nominal and high-resolution mass spectrometry.

We demonstrate that extraction through a hydrophobic membrane resolved the classically defined NA fraction from the less hydrophobic dissolved organic matter.

Factors influencing permselectivity at the membrane level, were examined with a series of model compounds with octanol-water partition constants ranging from logKow ~2–5.

This work demonstrates the use of membrane extraction for the selective sampling and determination of NAs and other trace organic contaminants in polluted waters, providing convenient sample clean-up prior to conventional analysis as well as direct, on-line detection by mass spectrometry.