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

Metabolomics is gaining consideration as a viable approach to diseases detection and even shows promising results in COVID-19 diagnosis. This work extends the study of the relationship between extractable sweat compounds 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 PLS-DA, with specificity and sensitivity percentages greater than 80%, revealed significant differences between the DI-SPME profiles of infected and non-infected patients. Six key peaks used in the classification model were annotated as undecanal, methyl palmitoleate, palmitic acid, methyl oleate, squalene, and methyl cerotate, based on NIST17 spectral matches (> 90%) and interpretation aided by retention index (RI) data. Palmitic acid and Methyl oleate signals were elevated in COVID-positive patients,while undecanal, methyl palmitoleate, squalene and methyl cerotate were detected in lower amounts in COVID-positive patients. The identified set of compounds may serve as potential biomarkers for COVID-19 disease, not only in serologic assessments but also in the development of non-invasive diagnostic approaches, such as sweat-based or volatilome-based testing, as well as for monitoring disease progression and patient recovery.