INVESTIGATION OF THE ANALYTICAL CAPABILITIES OF FOURIER TRANSFORM MASS SPECTROMETRY

Fourier transform mass spectrometry (FTMS) is investigated as a new approach to analytical mass spectrometry. The desired qualities of an ideal analytical mass spectrometric instrument are outlined and the degree to which FTMS satisfies these ideal requirements is evaluated. With respect to mass analysis, it is demonstrated that FTMS is capable of ultra-high mass resolution (600,000 FWHH definition at mass 156) which is easily obtained when low analyzer cell pressures (10(\u27-9) torr) are employed. Although resolution and sensitivity are inversely related for double focussing instruments, it is shown that both resolution and sensitivity can be simultaneously increased with FTMS. Further improvement in FTMS mass resolution is obtained using a convolution-based phase correction procedure. An analysis of the electric and magnetic fields present in the analyzer cell is used to derive a calibration equation which accurately relates frequency to mass under FTMS operating conditions. Exact mass measurements of sufficient accuracy and precision (2-5 ppm) to permit elemental composition assignments over a 158 amu mass range are demonstrated. The coupling of capillary gas chromatography to two different FTMS instruments using a molecular jet separator interface is described. It is shown that the GC/FTMS combination is capable of rapid scanning, high resolution mass analysis, peak switching over arbitrarily wide mass ranges, and chemical ionization of eluting GC components. Complex mixture analysis is further simplified using a GC/FT-IR/FTMS combination to obtain complementary infrared and mass spectrometric data on eluting components. An evaluation of low pressure collision-induced dissociation (FTMS-CID) for complex mixture analysis is presented. High mass resolution (10,000 FWHH definition at mass 43) of daughter ions is demonstrated and theoretical aspects of the experiment are discussed. A comparison of results of this CID procedure with those obtained using a triple quadrupole mass spectrometer is made. The analytical utility of low pressure gas phase ion-molecule reaction studies is investigated. Ion-molecule reaction rate constants are quickly and easily estimated. Gas phase deuterium exchange is used to elucidate structures of both positive and negative ion species