Radiant energy – Ionic separation or analysis – Methods
Patent
1989-04-21
1990-06-12
Berman, Jack I.
Radiant energy
Ionic separation or analysis
Methods
H01J 4948
Patent
active
049335472
ABSTRACT:
An ion cyclotron resonance mass spectrometer is externally calibrated, i.e. a calibrant compound is not present at the same time as the sample to be analyzed, by determining changes in the relative number of ions in the cell. This may be done by obtaining a spectrum of the sample to be analyzed, measuring the trapping sidebands, and then determining the trapping frequency from those sidebands as the difference between the trapping sideband frequencies and divided by four. The cyclotron frequency can then be found from the effective measured frequency and the trapping frequency, and the mass is then obtained as a function of the cyclotron frequency. Another approach is to measure the magnetron frequency directly, and then to calculate the cyclotron frequency from the measured effective frequency and the magnetron frequency. A third approach is to introduce a calibrant compound into the cell and produce several output signals with various relative numbers of ions. Calibration is accomplished by using the known relation
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Berman Jack I.
Extrel FTMS, Inc.
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