Development and Validation of a Method for the Simultaneous Quantification of 21 Microbial Volatile Organic Compounds in Ambient and Exhaled Air by Thermal Desorption and Gas Chromatography–Mass Spectrometry

Abstract

Microbial volatile organic compounds (mVOCs) are metabolites developed by indoor molds responsible for several health effects. Their detection may be an alternative approach for fungal exposure assessment, given that the classical methods have limitations. The goal of this study was to develop and validate an analytical method to quantify 21 mVOCs in ambient and exhaled air using active sampling on sorbent tubes followed by thermal desorption and gas chromatography–mass spectrometry analysis. Tenax/Carbograph sorbent was selected for its extraction/desorption efficiency. Reliable linearity was obtained over the concentration range of mVOCs with low limits of detection (≥1.76 ng/m3) and quantification (≥5.32 ng/m3). Furthermore, accuracy and precision in the percentage recoveries ranged between 80–118% with coefficients of variations lower than 4.35% for all mVOCs. Feasibility tests with ambient air of different places (toxicology laboratory, office, and mold contaminated bedroom) showed that variations between settings were observable and that the highest mVOCs concentrations in the bedroom. Consequently, concentrations of 17 mVOCs were higher in the volunteer’s exhalate after exposure in the bedroom than in the laboratory. In conclusion, this method allows the detection of mVOCs in a new matrix, i.e., exhaled air and targeting the contaminated environment and, therefore, intervening for the protection of human health.

Microbial volatile organic compounds measured in the air of a waste sorting plant and a university by thermal desorption-gas chromatography-tandem mass spectrometry

“…Stainless steel sorbent tubes (Tenax TA/Carbograph 1 TD) (Markes International, Llantrisant, UK) capped with ¼-inch brass storage caps, showing better adsorption results for the selected mVOCs (Tabbal et al, 2022b), were used for mVOCs collection. Tubes conditioning was performed before the rst use or if kept uncapped for more than one week.…”

“…A stock solution (SS) was prepared by adding 20 µL of each of the 21 compounds into 20 mL of methanol with individual mVOC concentration of 800-1000 mg/L. SS was then diluted 20-fold in methanol to obtain an intermediate solution (IS) with an individual mVOC concentration of 40-50 mg/L (Tabbal et al, 2022b). Calibration was carried out with IS.…”

“…In addition, the levels of 3-octanone, 1-octen-3-ol, 2-nonanone, 2-hexanone, toluene and 2-methyl-3-pentanol were associated with higher microbial contamination (Wang et al, 2016b) and 3-octanone, 2-octen-1-ol and 1-octen-3-ol were found at elevated levels in the presence of elevated amounts of molds and can possibly be considered as mVOCs with potential for serving as indicators of mold presence (Ryan & Beaucham, 2013). Therefore, due to their ability to pass through porous materials (mVOC's volatility) and their mold speci c production, some mVOCs can be valuable mold indicators and even potential biomarkers of mold exposure (El Aroussi et al, 2018; Garcia-Alcega et al, 2017; Tabbal et al, 2022aTabbal et al, , 2022b. In this study, the focus is on the measurement of mVOCs which can be considered as biomarkers of mold exposure rather than compounds that can cause health effects.…”

“…This method was selected for mVOCs sampling and analysis in the present study given that it presents multiple advantages such as (i) low cost, (ii) simple and effortless use of sorbent tubes, (iii) high recovery for reactive and polar compounds (Peng & Batterman, 2000;Ribes et al, 2007), (iv) high sensitivity since the dilution of the sample is not necessary (De Bortoli et al, 1992;Peng & Batterman, 2000), and (v) rapid detection of desorbed mVOCs without the need of sample preparation (Garcia-Alcega et al, 2017; Kozicki et al, 2019). In line with this, a sorbent-based analytical method using thermal desorption coupled to gas chromatography-triple quadrupole mass spectrometry (TD-GC-MS/MS) for quanti cation of 21 selected mVOCs was recently developed for ambient and exhaled air (Tabbal et al, 2022b) and remains to be tested and optimized in pertinent indoor environments such as waste management facilities.…”

“…These 21 mVOCs, whose properties correspond to the biomarker approach for the assessment of mold exposure, were selected based on the review done by El Aroussi et al, (2018). Mainly, the choice of these compounds was based on the health interest (species of mold known for their health effects), the occurrence of emissions and the mVOCs physicochemical (pH and boiling temperature) and pharmacokinetic (blood:air partition coe cient and volume of distribution) properties (El Aroussi et al, 2018;Tabbal et al, 2022b).…”