Salivary Volatile Organic Compound Analysis: An Optimised Methodology and Longitudinal Assessment Using Direct Injection Mass Spectrometry

Analysis of salivary volatile organic compounds (VOCs) may offer a novel noninvasive modality for disease detection. This study aims to optimise saliva headspace VOC analysis and assess longitudinal variation VOCs. Whole from healthy participants was acquired in order four methodological parameters: collection, volume, dilution, acidification. Saliva VOCs were analysed using untargeted proton transfer reaction time-of-flight mass spectrometry. Using the optimised method, five samples collected over 3 weeks assessed variability reproducibility with targeted selected ion flow tube-mass spectrometry analysis. The method collection influenced detection source contamination. An amount 500 µL whole by passive drool yielded optimal Longitudinal negligible target short chain fatty acids aldehydes. However, certain showed suggesting influence potential exogenous factors. Overall, there an acceptable range inter- intraindividual variability. Standardisation morning sampling after 6 h fast is recommended demonstrating minimal intersubject Future studies should seek establish levels diseased populations.