Quantitative mass spectrometric identification of isomers applying coherent laser control

Mass spectrometry (MS) is one of the oldest and most trusted analytical methods for chemical identification. Advances in biology, such as metabolic analysis and proteomics, have fueled a growing number of refinements in this method. Unfortunately, isomers, for example, o- and p-xylene, are seldom identifiable by MS because they produce identical spectra. Time-consuming and less sensitive multidimensional methods are subsequently required for structural determination. The sensitivity of MS coupled with shaped femtosecond laser pulses that control molecular fragmentation and ionization results in a new, fast, and reproducible method for molecular identification which is used here to distinguish positional and geometric isomer compounds and quantify their relative concentration in mixtures.