Parametric Studies of Condensed Phase Membrane Introduction Mass Spectrometry (CP-MIMS): Membrane Types/Geometries, Acceptor Phase Modifications and Continuous Online Quantitation Techniques

摘要

Condensed phase membrane introduction mass spectrometry (CP-MIMS) uses a condensed (liquid) acceptor phase to transfer analytes from a membrane sampling interface to a direct liquid ionization mass spectrometer (e.g. ESI-MS). Having a condensed acceptor phase allows for the transport of larger, more polar, and less volatile analytes, those that would normally not pervaporate into a gaseous acceptor phase. We have been exploring the development of CP-MIMS in our group, and have found the technique is amenable to direct, continuous, on-line, trace level monitoring of a wide range of contaminants and bio-analytes. This work explores several avenues for this emerging method, including the use of different membrane geometries (e.g. sheet versus hollow fibre membranes), membrane materials such as polydimethylsiloxane (PDMS) and Nafion~R, optimization of acceptor phase conditions for both analyte permeation and ionization, as well as the evaluation of various on-line quantitation strategies. The use of CP-MIMS for direct bio-analytical measurements of trace drugs of abuse and their metabolites in complex samples (e.g. artificial urine) has also been examined.