A simple comparison of mass spectral search results and implications for environmental screening analyses

A simple assessment of the ability of environmental laboratories to perform automated library searching procedures on mass spectra of unknown pollutants was conducted. In this assessment, 10 laboratories analyzed a hexane solution containing eight organic chemicals using gas chromatography/mass spectrometry and searched their acquired mass spectral data against mass spectral reference libraries. The search results were used to evaluate the similarity of the lists of tentative identifications (TIDs) among the laboratories and to compare the observed searching success to the searching success reported in the literature using high-quality mass spectral data. A high degree of similarity was observed among the lists of TIDs reported by the laboratories for each chemical. The searching success observed in this study was slightly lower than that reported in the literature based on higher-quality mass spectral data. This simple comparison suggests that laboratories performing routine environmental analyses can successfully perform automated searching procedures for unknown sample components, and that the mass spectral searching component of analytical methods designed to screen for unknown organic pollutants should be successful, i.e., obtain similar and reproducible results among laboratories.