Selected ion flow tube mass spectrometry for targeted analysis of volatile organic compounds in human breath

Hybrid learning method based on feature clustering and scoring for enhanced COVID-19 breath analysis by an electronic nose

“…The ratios describing the differences of expiratory and inspiratory concentrations and the alveolar concentration could be calculated to approximate the alteration of inhaled and exhaled substances. Here, blood-borne volatile substances with clearly exogenous (e.g., 2-butanone and 2-propanol) and endogenous (e.g., acetone, isoprene, and CO 2 ) origins typically obtained low (<1) and high (>1.5) ratio values, respectively [23] , [84] . After inserting the third exhaled breath into the sampling bag, its valve was quickly closed to avoid any air leakages.…”

“…In terms of the human breath analysis for COVID-19 detection, mass spectrometry (MS), which is versatilely coupled with various chromatographic separation methods, can be employed to better understand the clinical and biochemical processes of COVID-19 [20] . Among the available variants, the selected-ion flow-tube MS (SIFT-MS) [23] , proton-transfer reaction MS (PTR-MS) [24] , [25] , and gas chromatography–MS (GC–MS) [26] with thermal desorption or solid-phase microextraction have been attempted to be utilized for COVID-19 diagnosis, in which MS-detected exhaled breath biomarkers can identify RT-qPCR-confirmed positive COVID-19 patients with high sensitivity.…”

Variation of volatile organic compound levels within ambient room air and its impact upon the standardisation of breath sampling

“…A custom-made, single use Nalophan™ (PET-polyethylene terephthalate) bag with a 1000 mL capacity and a polypropylene syringe acting as a sealable mouthpiece was utilised for the collection of breath as previously described by Belluomo et al . 2 . Nalophan has been demonstrated to be a good medium for breath storage due to its inertness and ability to provide compound stability for up to 12 h 38 .…”

“…One crucial area of interest for breath analysis standardisation is the potential effect of background VOCs within the ambient room air 2 . Previous studies have suggested that background VOCs within the ambient room air influence the levels of VOCs detected within exhaled breath 3 .…”

Acetone Sensor Based on FAIMS-MEMS

“…However, patients are usually resistant to this method because it causes damage to skin tissues and is accompanied by an obvious stinging sensation, and there are unsafe factors that can easily cause infection. Therefore, the development of a noninvasive detection technique has become a hot spot in medical research, and breath analysis, as a new noninvasive detection technique, has been favored by many researchers [2][3][4][5][6][7][8]. Studies have shown that the human breath contains more than 1000 volatile organic compounds (VOCs) [9].…”