Solid-phase microextraction of sweat components of patients positive for Sars-Cov-2 for identification of possible biomarkers

Metabolome is gaining consideration as a viable approach to disease detection and even shows promising results in COVID-19 diagnosis. This work extends the study of the relationship between solid-phase microextraction (SPME) extractable sweat compounds (SPME-ECs) and COVID-19 positive patients. Sweat samples were collected from 426 patients (126 positives and 300 negatives) recruited at Merida and Progreso (Yucatán, México) health centers. The composition of sweat was analyzed with a solid phase microextraction gas chromatography-mass spectrometry (SPME-GC-MS) method. The statistical analysis revealed significant differences between infected and non-infected patients’ SPME-EC profiles. Then, we evaluated different classification models to discriminate between positive and negative patients. The best model was the PLS-DA model, with percentages of specificity and sensitivity above 80%. Six relevant chromatographic peaks for the classification model were annotated (hexadecanoic acid, tetracosanoic acid, 6-hexadecenoic acid, oleic acid, squalene, and undecanal) based on the mass spectrum recognition using the NIST library (> 90% identity match). Palmitic and oleic acid signal was elevated in COVID-positive patients. While sapienic acid, lignoceric acid, squalene, and undecanal were detected in lower amount in COVID-positive patients. The present list of chemical opens the possibility to be used as a reliable serologic biomarker.