Enhancement of ion activation and collision induced dissociation by direct current potential in digital ion trap mass spectrometer

Abstract

The efficiency of collision induced dissociation (CID) is strongly dependent on the ion activation energy. In order to increase the ion kinetic energy during resonance ion excitation, a DC voltage was deduced by simply changing the duty cycle of digital power supply in this study using a digital linear ion trap. In this experiment, different DC potentials were obtained by choosing different duty cycles of main ion trapping digital waveform, and the waveforms applied to the x and y electrode pairs were kept complimentary during ion activation and CID period. The experimental results shown that the CID efficiency was significantly increased when the DC potential was increased. The observed ion internal energy was increased about 2.5 times, and the CID efficiency was increased from 68% to 93%. A calculation shows that the low mass cut off can also be reduced by 15% and it is in agreement with the experiment results.