| 主权项 |
1. A method for obtaining a mass spectrum of biomolecular ions, the method comprising:
providing a two dimensional linear ion trap comprising x and y electrodes, wherein the x and y electrodes are two x electrode rods and two y electrode rods in a quadrupole arrangement; scanning an RF frequency applied to the linear ion trap for mass selective ejection of the ions by using two power amplifiers to apply opposite phases of the RF to the x and y electrodes, wherein each power amplifier is tuned with a capacitance to provide the same amplitude of RF and a fixed degree of phase difference of the RF to the x and y electrodes during the RF frequency scan; detecting the biomolecular ions ejected from the linear ion trap using a charge detector, wherein the ions have an m/z of at least 400,000 Da/q. |
