AN ELECTROSTATIC ION TRAP MASS SPECTROMETER UTILIZING AUTORESONANT ION EXCITATION AND METHODS OF USING THE SAME

摘要

Methods of operation of electrostatic ion trap mass spectrometers in which ions are autoresonantly driven at selected higher integer (>2) multiples of ion oscillation frequencies are provided. Excitation at multiples higher than the fundamental or double the fundamental ion oscillation frequency significantly improves both signal intensity and mass resolution. Each method allows excitation exclusively at one selected frequency that is an integer multiple of an ion's natural oscillation frequency, and thereby virtually eliminates ion excitation at unwanted harmonic frequencies. The resultant mass spectra are therefore clean, and do not display spectral features associated with rf excitation at unintended multiple harmonic frequencies.