Rapid differentiation of cystic fibrosis-related bacteria via reagentless atmospheric pressure photoionisation mass spectrometry.

Haworth-Duff, Adam, Smith, Barry L, Sham, Tung-Ting ORCID: 0000-0002-9648-4964, Boisdon, Cedric, Loughnane, Paul, Burnley, Mark, Hawcutt, Daniel B ORCID: 0000-0002-8120-6507, Raval, Rasmita and Maher, Simon (2024) Rapid differentiation of cystic fibrosis-related bacteria via reagentless atmospheric pressure photoionisation mass spectrometry. Scientific reports, 14 (1). p. 17067. ISSN 2045-2322, 2045-2322

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Abstract

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 > 0.99 and limits of detection < 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.

Item Type:	Article
Uncontrolled Keywords:	Humans, Pseudomonas aeruginosa, Escherichia coli, Staphylococcus aureus, Cystic Fibrosis, Breath Tests, Atmospheric Pressure, Mass Spectrometry, Volatile Organic Compounds
Depositing User:	Symplectic Admin
Date Deposited:	05 Aug 2024 07:16
Last Modified:	08 Dec 2024 03:09
DOI:	10.1038/s41598-024-66851-y
Related URLs:	Author Publisher
URI:	https://livrepository.liverpool.ac.uk/id/eprint/3183315