Determining elemental compositions from exact masses and relative abundances of ions

A new scanning strategy permits on-line determination of exact masses and relative abundances of ions produced from analytes as they are separated chromatographically and analyzed by a high-resolution mass spectrometer. Tentative identifications of compounds based on library matches of their background subtracted mass spectra can now be confirmed or refuted by applying 6 criteria based on the molecular ion (M), M + 1, and M + 2 mass peak profiles, This article reviews the technique, demonstrates its most common application, and lists some of its other uses.