Calculating the numerical similarity between high-resolution mass spectra of biological samples collected with ambient ionization mass spectrometry

<jats:p>High-resolution mass spectral measurements of biological data collected with ambient ionization mass spectrometry have inherent complexities. Biological samples are complex mixtures of chemical compounds, and ambient ionization techniques are not preceded by separation processes that reduce the number of observable compounds in a given mass spectrum. In this technical note, we detail a specific procedure for processing and comparing high-resolution mass spectra that leverages contextual, biological information, when computing similarity scores. We demonstrate the procedure with example mass spectra from the Forensic Spectra of Trees (ForeST©) Database.</jats:p>