We propose to upgrade our Nicolet FTMS-1000 Fourier transform mass spectrometer to a Nicolet FTMS-2000 with 8 tesla magnet. The present vacuum system and cart, cell assembly and mount, and vacuum pumps will be exchanged for new versions, and the excitation amplifier will be upgraded to higher output voltage. The existing console and data system will be retained. The new system will provide both qualitative and quantitative improvements. The most important new feature will be the capability for reliable gas chromatography/FT/MS at high mass resolution; those experiments cannot be performed on the FTMS-1000, except for specially chosen samples. In addition, several quantitative improvements are so great as to offer qualitatively new capability: (a) rapid sample changing (10 min compared to up to 2 hours presently required on the FTMS-1000); (b) improved signal-to-noise ratio (at least a factor of 5), due to ion formation at high pressure with detection at low pressure; (c) enhanced resolution (at least a factor of 5) due to lower pressure at the detector; (d) two-inch sample cell rather than one-inch, resulting in a doubling of signal-to-noise ratio and doubling of mass resolution, as well as improved line shape due to reduced Coulomb broadening; (e) mesh rather than solid cell plates, providing for more efficient pump-down conductance during GC and/or on changing samples; (f) reduced pressure at the detector, allowing for exact mass determination during laser desorption/ionization experiments. The higher magnetic field will increase signal-to-noise ratio (2.66X) and mass resolution (2.66X) and reduce data acquisition time (7.1X). Time-shared """"""""tailored"""""""" excitation (i.e., """"""""stochastic"""""""" excitation) will be developed for FT/MS, providing software-interchangeable: (a) flat excitation power for precise isotope-ratio measurement, (b) windowed excitation for increased dynamic range or MS/MS with high mass resolution, and (c) the first simultaneous multiple-ion monitoring capability. These methods will be applied toward mass spectrometric analysis of synthetic and natural drugs and metabolites.
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