Big Free-Access Chemical Databases in Non-Target Mass Spectrometry Analysis

The ChemSpider and PubChem chemical databases used in non-target mass spectrometry analysis in order to outline the candidates for identification are described. Relevant compounds are searched by molecule-containing ion masses (only ChemSpider) or by molecular formulas before determined (both databases). The compounds that are highly cited and information-rich are candidates for identification. PubChem contains more direct information on the properties and use of chemical compounds than that in the other database. These data give evidence of the likelihood of identification. Final decisions on identification are made with the traditional use of reference analytical data (mass spectra and chromatography retention parameters) and analytical reference materials.