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 sep arated chromatographically and analyzed by a high-resolution mass spec trometer. Tentative identifications of compounds based on library matc hes of their background subtracted mass spectra can now be confirmed o r refuted by applying 6 criteria based on the molecular ion (M), M + 1 , and M + 2 mass peak profiles, This article reviews the technique, de monstrates its most common application, and lists some of its other us es.