Direct and Reagentless Atmospheric Pressure Photoionisation Mass Spectrometry: Rapid and Accurate Differentiation of Cystic Fibrosis Related Bacteria by Monitoring VOCs

Haworth-Duff, Adam ORCID: 0009-0001-2065-9369, Smith, Barry L ORCID: 0000-0001-5571-3647, Sham, Tung-Ting, Boisdon, Cedric, Loughnane, Paul, Burnley, Mark, Hawcutt, Daniel B ORCID: 0000-0002-8120-6507, Raval, Rasmita and Maher, Simon (2024) Direct and Reagentless Atmospheric Pressure Photoionisation Mass Spectrometry: Rapid and Accurate Differentiation of Cystic Fibrosis Related Bacteria by Monitoring VOCs [Preprint]

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Abstract

<title>Abstract</title> <p>Breath analysis is an area of significant interest in medical research as it allows for non-invasive sampling with exceptional potential for disease monitoring and diagnosis. Volatile organic compounds (VOCs) found in breath can offer critical insight into a person’s lifestyle and/or disease/health state. To this end, the development of a rapid, sensitive, cost-effective and potentially portable method for the detection of key compounds in breath would mark a significant advancement. Herein we have designed, built and tested a novel reagent-less atmospheric pressure photoionisation (APPI) source, coupled with mass spectrometry (MS), utilising a bespoke bias electrode within a custom 3D printed sampling chamber for direct analysis of VOCs. Optimal APPI-MS conditions were identified including bias voltage, cone voltage and vaporisation temperature. Calibration curves were produced for ethanol, acetone, 2-butanone, ethyl acetate and eucalyptol, yielding R² &gt; 0.99 and limits of detection &lt; 10 pg. As a pre-clinical proof of concept, this method was applied to bacterial headspace samples of Escherichia coli (EC), Pseudomonas aeruginosa (PSA) and Staphylococcus aureus (SA) collected in 1 L Tedlar bags. In particular, PSA and SA are commonly associated with lung infection in cystic fibrosis patients. The headspace samples were classified using principal component analysis with 86.9% of the total variance across the first three components and yielding 100% classification in a blind-sample study. All experiments conducted with the novel APPI arrangement were carried out directly in real-time with low-resolution MS, which opens up exciting possibilities in the future for on-site (e.g., in the clinic) analysis with a portable system.</p>

Item Type:	Preprint
Uncontrolled Keywords:	3401 Analytical Chemistry, 31 Biological Sciences, 32 Biomedical and Clinical Sciences, 34 Chemical Sciences, 3107 Microbiology, Lung, Cystic Fibrosis, Bioengineering, Infectious Diseases, Rare Diseases, 4.1 Discovery and preclinical testing of markers and technologies, Infection
Divisions:	Faculty of Health & Life Sciences Faculty of Science & Engineering > School of Electrical Engineering, Electronics and Computer Science Faculty of Health & Life Sciences > Inst. Life Courses & Medical Sciences
Depositing User:	Symplectic Admin
Date Deposited:	21 Mar 2024 09:14
Last Modified:	15 Jan 2026 21:18
DOI:	10.21203/rs.3.rs-3976993/v1
Related Websites:	Publisher
URI:	https://livrepository.liverpool.ac.uk/id/eprint/3179763
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