Research Of Digital Quadrupole Mass Filter Based On Frequency Scan

In this centry, owing to the increasing demand and rapid improvement of the analysis of biomolecular ions, tandem mass spectrometry has experienced an unimageable growth, and becomes pivotal one in mass spectrometry(MS) used in the analysis area. However, the research of tandem mass spectrometry in China is unsatisfactory, and all of tandem mass spectrometry instruments are imported from foreign countries, like USA, Japan, and German. For this reason, in China, It's of significance to develop the research of tandem mass spectrometry instrument. In this thesis some research were done about a type of tandem mass spectrometry used in the analysis of ions whose masses are great like large biomolecular ions.In order to solve the problem which come from the extra-high voltage used to filter large ions,this thesis change the style of driving voltage which is not a sinusoidal or cosinoidal wave voltage but a rectangular wave voltage. In the same time, mass scans are achieved by changing frequency, instead of changing the RF voltage amplitude, or sometimes with a proportional dc voltage component.In this thesis, after the review the fundamental principles of traditional sinusoidal or cosinoidal wave driving the quadrupole mass filter, the validity of rectangular wave as the driving voltage of the quadrupole mass filter was establishded by a great number of essential calculations. Moreover, the stability diagram for the quadrupole mass filter driven by rectangular wave and the diagram of frequency scan plotted in the T-DC space has been calculated, and the scan line is also drawn in this thesis. This is followed by the computer simulation study of the digital quadrupole mass filter to confirm the Correction of calculation. Finally, the electric circuit and mechanical design are presented.The research of digital quadrupole mass filter based on the frequency scan in this thesis demonstrated applicability of digital quadrupole mass filter which are used to filter large biomolecular ions from both calculation and computer simulation. It is significant to further the research of digital quadrupole mass filter including the development of the device.