Delicate polydimethylsiloxane hollow fibre membrane interfaces for condensed phase membrane introduction mass spectrometry (CP‐MIMS). (13th February 2014)

• Record Type: Journal Article
• Authors: Willis, Megan D.; Duncan, Kyle. D.; Krogh, Erik T.; Gill, Chris G.
• Is Part Of: Rapid communications in mass spectrometry. Volume 28:Number 7(2014)
• Page Start: 671
• Page End: 681
• Publication Date: 2014-02-13
• Subjects: Mass spectrometry -- Periodicals; 543.65
• DOI: 10.1002/rcm.6828
• Languages: English
• ISSNs: 0951-4198

Abstract

<abstract abstract-type="main"> <title> <x xml:space="preserve">Abstract</x> </title> <sec id="rcm6828-sec-0001" sec-type="section"> <title>RATIONALE</title> <p>On‐line analytical techniques such as condensed phase membrane introduction mass spectrometry (CP‐MIMS) permit direct and rapid analyte measurements in complex samples. Direct, rapid analytical methods are desirable because they eliminate potential contamination and/or dilution from sample workup steps, facilitate rapid sample screening and allow 'real‐time' monitoring applications.</p> </sec> <sec id="rcm6828-sec-0002" sec-type="section"> <title>METHODS</title> <p>PDMS hollow fibre membrane (HFM) flow cell interfaces (215 µm, 35 µm, and 0.5 µm thick composite) were coupled with an electrospray ionization (ESI) triple quadrupole mass spectrometer. A simultaneous push/pull methanol acceptor phase delivery system and membrane mounting via epoxy potting ensured that the delicate membranes were not ruptured during construction or sample measurements. Both flow cell and direct insertion 'J‐Probe' interfaces using the 0.5 µm thick composite PDMS HFM were utilized for direct naphthenic acid measurements.</p> </sec> <sec id="rcm6828-sec-0003" sec-type="section"> <title>RESULTS</title> <p>Delicate HFM CP‐MIMS interfaces were used for the rapid screening and continuous, on‐line monitoring of carboxylic acids and hydroxylated compounds directly in complex sample matrices under ambient conditions at pptr – ppb detection limits. Push/pull acceptor phase (methanol) delivery maintained ambient hydrostatic pressures within the HFMs, improving ESI stability and analytical sensitivity, especially with stopped acceptor flow operation. Signal response times less than 2 min were achieved for thin, composite PDMS HFMs at 30°C. The continuous monitoring of naphthenic acid degradation was demonstrated.</p> </sec> <sec id="rcm6828-sec-0004" sec-type="section"> <title>CONCLUSIONS</title> <p>Delicate PDMS HFM CP‐MIMS interfaces were developed and used for the direct, on‐line detection of low volatility, polar analytes in complex aqueous samples. Composite PDMS HFM interfaces yielded the best overall analytical performance improvements, and were used to demonstrate the direct measurement of naphthenic acids in complex aqueous samples. Copyright © 2014 John Wiley & Sons, Ltd.</p> </sec> </abstract>