Assessment of a combined gas chromatography mass spectrometer sensor system for detecting biologically relevant volatile compounds

Gould, Oliver; Ratcliffe, Norman M; De Lacy Costello, Ben; Wieczorek, Tom; Persad, Raj

Abstract

© 2017 IOP Publishing Ltd. There have been a number of studies in which metal oxide sensors (MOS) have replaced conventional analytical detectors in gas chromatography systems. However, despite the use of these instruments in a range of applications including breath research the sensor responses (i.e. resistance changes w.r.t. concentration of VCs) remain largely unreported. This paper addresses that issue by comparing the response of a metal oxide sensor directly with a mass spectrometer (MS), whereby both detectors are interfaced to the same GC column using an s-swafer. It was demonstrated that the sensitivity of an in-house fabricated ZnO/SnO2 thick film MOS was superior to a modern MS for the detection of a wide range of volatile compounds (VCs) of different functionalities and masses. Better techniques for detection and quantification of these VCs is valuable, as many of these compounds are commonly reported throughout the scientific literature. This is also the first published report of a combined GC-MS sensor system. These two different detector technologies when combined, should enhance discriminatory abilities to aid disease diagnoses using volatiles from e.g. breath, and bodily fluids. Twenty-nine chemical standards have been tested using solid phase micro-extraction; 25 of these compounds are found on human breath. In all but two instances the sensor exhibited the same or superior limit of detection compared to the MS. Twelve stool samples from healthy participants were analysed; the sensor detected, on average 1.6 peaks more per sample than the MS. Similarly, analysing the headspace of E. coli broth cultures the sensor detected 6.9 more peaks per sample versus the MS. This greater sensitivity is primarily a function of the superior limits of detection of the metal oxide sensor. This shows that systems based on the combination of chromatography systems with solid state sensors shows promise for a range of applications.

• Journal Article Type: Article
• Acceptance Date: Sep 26, 2017
• Online Publication Date: Dec 6, 2017
• Publication Date: Jan 1, 2018
• Deposit Date: Oct 18, 2017
• Publicly Available Date: Dec 6, 2018
• Journal: Journal of Breath Research
• Print ISSN: 1752-7155
• Electronic ISSN: 1752-7163
• Publisher: IOP Publishing
• Peer Reviewed: Peer Reviewed
• Volume: 12
• Issue: 1
• Pages: 016009
• DOI: https://doi.org/10.1088/1752-7163/aa8efe
• Public URL: https://uwe-repository.worktribe.com/output/872735
• Publisher URL: https://doi.org/10.1088/1752-7163/aa8efe
• Additional Information: Additional Information : This is an author-created, un-copyedited version of an article published in Journal of Breath Research. IOP Publishing Ltd is not responsible for any errors or omissions in this version of the manuscript or any version derived from it. The Version of Record is available online at https://doi.org/10.1088/1752-7163/aa8efe
• Contract Date: Oct 18, 2017