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J Breath Res

Title:		Volatile organic compounds in a headspace sampling system and asthmatics sputum samples
Author(s):		Peltrini R; Cordell RL; Ibrahim W; Wilde MJ; Salman D; Singapuri A; Hargadon B; Brightling CE; Thomas CLP; Monks PS; Siddiqui S;
Address:		"University of Leicester, Department of Respiratory Sciences, LE1 7RH Leicester, United Kingdom. University of Leicester, Department of Chemistry, LE1 7RH Leicester, United Kingdom. Leicester NIHR Biomedical Research Centre (Respiratory theme), Glenfield Hospital, Groby Road, LE3 9QP Leicester, United Kingdom. Department of Chemistry, Loughborough University, Loughborough LE11 3TU, United Kingdom"
Journal Title:		J Breath Res
Year:		2021
Volume:		20210111
Issue:		2
Page Number:		-
DOI:		10.1088/1752-7163/abcd2a
ISSN/ISBN:		1752-7163 (Electronic) 1752-7155 (Linking)
Abstract:		"The headspace of a biological sample contains exogenous volatile organic compounds (VOCs) present within the sampling environment which represent the background signal. This study aimed to characterise the background signal generated from a headspace sampling system in a clinical site, to evaluate intra- and inter-day variation of background VOC and to understand the impact of a sample itself upon commonly reported background VOC using sputum headspace samples from severe asthmatics. The headspace, in absence of a biological sample, was collected hourly from 11am to 3pm within a day (time of clinical samples acquisition), and from Monday to Friday in a week, and analysed by thermal desorption-gas chromatography-mass spectrometry (TD-GC-MS). Chemometric analysis identified 1120 features, 37 of which were present in at least the 80% of all the samples. The analyses of intra- and inter-day background variations were performed on 13 of the most abundant features, ubiquitously present in headspace samples. The concentration ratios relative to background were reported for the selected abundant VOC in 36 asthmatic sputum samples, acquired from 36 stable severe asthma patients recruited at Glenfield Hospital, Leicester, UK. The results identified no significant intra- or inter-day variations in compounds levels and no systematic bias ofz-scores, with the exclusion of benzothiazole, whose abundance increased linearly between 11am and 3pm with a maximal intra-day fold change of 2.13. Many of the identified background features are reported in literature as components of headspace of biological samples and are considered potential biomarkers for several diseases. The selected background features were identified in headspace of all severe asthma sputum samples, albeit with varying levels of enrichment relative to background. Our observations support the need to consider the background signal derived from the headspace sampling system when developing and validating headspace biomarker signatures using clinical samples"
Keywords:		*Asthma/diagnosis Breath Tests Gas Chromatography-Mass Spectrometry/methods Humans Sputum/chemistry *Volatile Organic Compounds/analysis background signal headspace analysis severe asthma sputum volatile organic compounds;
Notes:		"MedlinePeltrini, Rosa Cordell, Rebecca L Ibrahim, Wadah Wilde, Michael J Salman, Dahlia Singapuri, Amisha Hargadon, Beverley Brightling, Christopher E Thomas, C L Paul Monks, Paul S Siddiqui, Salman eng MR/N005880/1/MRC_/Medical Research Council/United Kingdom DH_/Department of Health/United Kingdom Research Support, Non-U.S. Gov't England 2020/11/24 J Breath Res. 2021 Jan 11; 15(2). doi: 10.1088/1752-7163/abcd2a"