The Research And Development Of Several New Ion Trap Mass Analyzers

Amongst numerous analysis and test methods, mass spectrometry analysis is known as a kind of method combine the merits of high specificity and high sensitivity, and is one of the most widely used analysis methods in the world. Now mass spectrometer is not only noted and widely applied in many scientific research fields but also plays a important role in environment monitoring, food safety etc. Unfortunately, although mass spectrometry analysis has a pivotal position in analysis field, due to the bulky volume, high price and the huge later maintenance costs, the large-scale popularization and application are restricted. At present, in the process of lots of analysis, people prefer the real-time, in-situ analysis rather than collecting samples and sending to the laboratory for test, for example the environmental monitoring, the dangers and explosives detection in some emergency circumstances, industrial production process monitoring, etc. It is inevitably to do some repeat analysis processes in the analysis procedure, such as parallel testing of a mass of drugs or biological samples, the routine analysis flux of existing instruments greatly restricted the analysis speed and also adding the testing instruments will increase the cost. So the portable miniaturized and high throughput mass analyses are now become the two important directions for the developments of modern mass spectrometers.With the development of Chinese economy, more and more people now know the mass spectrometry analysis and use it, the requirements for mass spectrometer are becoming more and more large.according to the related report, there were about 300 mass spectrometry related instruments imported in 2003, and in 2005 this number raised to 950, in 2007 this number arrived to 1700, in the years 2009 and 2010 the imported instruments numbers are 3600 and 4000 independently, up until now the imported number is over 5000, even worse the numbers keep raising every year. But due to the late start of Chinese mass spectrometer industry and with less support in the starting period, the Chinese market of mass spectrometer is almost completely occupied by foreign products. Obviously, it is urgent to develop our own mass spectrometers. Recent years, the Chinese government pays considerable attention to the research and development of mass spectrometer. During National Key Technology R&D Program in the 10th Five years plan of China The research and development of scientific instruments and in the next 11th Five years plan The research and development of scientific instruments, there were all with the sub-items of the core technology and critical components of mass spectrometer. At present the domestic mass spectrometer markets have already made some encouraging achievements, but on the whole there is still a large gap between domestic and international front edge in actual mass analysis performance because of the lack of key technology and intellectual property right.In view of the present situation of mass spectrometer research and development and the needs of miniaturization, portable, high throughput mass analysis and proprietary intellectual property rights, we choose linear ion trap as the direction of research. In the present numerous mass spectrometer instruments, ion trap mass analyzer has its own unique advantages:simple structure, compact size, tandem mass analysis capability and mild requirement of vacuum and all these advantages are all of great importance for the portable miniaturized and high throughput mass analysis of mass spectrometer. In the early 1950s Paul and coworkers proposed a 3D ion trap called Paul trap, this ion trap was composed of 3 electrodes, include 2 end cap electrodes and a ring electrodes, the working surface of these electrodes were all hyperboloid. As the radio-frequency voltages applied on the electrodes, the ion storage in 3D ion trap is 3D storage mode, all the ions in the trap will move toward the center and gather there in a little group space, the huge coulomb force interactions between these ions will leads the low trapping capacity and low trapping efficiency for externally injected ions. In order to avoid this problem in 3D ion traps, linear ion trap was proposed. Linear ion trap is a 2D ion trap, the sample ions are trapped using a radio frequency (RF) field in the radial direction, while in the direction along the quadrupole axis the trapping field was a constant field created by a DC potential. This 2D radio frequency (RF) applies method change the ion storage from group to the radial direction linear storage. In this way, as the ion cloud distributes along the quadrupole axis, the trapping efficiency and charge capacity can be greatly improved and the space charge effect can also be highly reduced. In the linear ion trap, there are sample entry on both sides of the electrodes, and generally speaking the sample inlet is situated at the center of the end cap electrodes at both ends, at this position the electric field intensity is the weakest and it can lead to the result of nearly no RF field influence when the ions enter into the trap, so the ion storage efficiency of the linear ion trap can be close to 100% when the external ions are injected into the trap. Nowadays, commercial linear ion traps normally contain hyperbolic shaped electrodes, but the hyperbolic electrode system still requires high mechanical accuracy in fabrication and assembly. Nowadays the simplification of linear ion trap electrode structure is the main research direction. The main research field of this article is the miniaturization and high throughput mass analysis, the specific achievements include:(1) Design and machining the ion trap array mass analyzer with independent intellectual property rights, build up a high throughput mass analysis platform with atmospheric pressure interface, and use two of adjacent channel to accomplish the synchronization analysis of different samples successfully, which is high throughput mass analysis. Beside the high throughput mass analysis, the ions movement behavior between different channels was investigated as the synchronization* analysis of different samples was done.(2) Study the electrode simplified linear ion trap-triangular electrode linear ion trap (TeLIT) from the theoretical simulation and experiment aspects. From the perspective of theoretical simulation to analysis the performance of triangular electrode linear ion traps with different structures and detailed analysis of electric field, and choose the relatively optimal theoretical simulation results process into trap and use the electrospray ion source mass analysis platform to investigated the performance of TeLIT in experiment.(3) With further optimization of TeLIT, we propose a pentagonal electrode linear ion trap, and proved that it can used as the ion trap from the theoretical simulation, and with further structure optimization and field analysis, it is manufactured into a trap for further experiment.This thesis is divided into six chapters and the main content summary is listed as follows:Chapter 1:introduction. This chapter is mainly the introduce of the development of mass spectrometry and the classification of mass spectrometer instruments, and the analysis of the current status of mass spectrometer apparatus in domestic and abroad, and point out the development direction of mass spectrometer. This chapter emphatically elaborates the principle of ion trap, classification, characteristic and the evolutionary process of ion trap. Meanwhile it introduces the development and characteristic of linear ion trap. On the basis of these analyses, we put forward the research direction and research approach.Chapter 2:The research and development of Printed circuit board (PCB) ion trap array mass spectrometry. In this chapter, we introduced the process of designing the ion trap array (ITA) mass analyzer and its basic principle. An 1TA mass analyzer consists of only one pair of PCB electrodes and two pairs of rectangular electrodes made of stainless steel, and it has very simple structure and very low cost. However, the ITA is a powerful mass analyzer, for it has multiple mass analysis channels, and each channel has the functions of a conventional ion trap, which can be used as a independent mass analyzer. An electrospray ionization (ESI) source PC B-ITA mass spectrometer was also built to test its performance. Using this experiment platform ion storage, mass analysis, mass-selected ion isolation and mass-selected ion ejection were all tested.Chapter 3:The research and development of ceramic electrode ion trap array mass spectrometer. In this chapter, we introduce the process of designing the ceramic electrode ion trap array mass analyzer and its basic principle, this ion trap is made of gold coated ceramic plate electrode and stainless steel plate electrode, and it has the high throughput analysis ability. There arc multi-mass analysis channels in the ITA, each analysis channel can be used as a independent ion trap, and the channels on both sides was built with two ceramic electrodes and one border ground electrode, the middle channels are composed of two ceramic electrodes. All these channels use the public plate electrodes. There is no entity electrode between different channels, using the method of specific voltage applied to form the zero potential energy surface to accomplish the ion constraint. Compared to the rectangular linear ion trap, this ion trap array has a simpler structure. Using the homemade ESI ion source and atmospheric pressure interface secondary differential vacuum chamber analysis platform to test the ITA performance, and it is proved that it can used to achieve the high throughput mass analysis; at the same time we investigated the different ions behavior in different channels when analysing different samples.Chapter 4:The research and development of triangular electrode linear ion trap. In this chapter, we introduced a triangular electrode linear ion trap, it is a electrode structure simplified linear ion trap which is similar to the rectangular linear ion trap, but different with the rectilinear ion trap, this electrode simplified structure greatly decreases the inner high order field component. From the perspective of theoretical simulation we analyse the performance and electric field of triangular electrode linear ion traps with different structures, and choose the relatively optimal theoretical simulation results process into trap and use the electrospray ion source mass analysis platform to investigate the performance of TeLIT in experiment.Chapter 5:Simulation study of the triangular electrode ion trap and the pentagonal electrode ion trap. In this chapter the triangle electrode linear ion traps with different structure were studied the in detail using the method of simulation, mainly includes the electric field analysis and mass resolution. And based on the triangle electrode linear ion trap, we proposed a pentagonal electrode linear ion trap. From the theoretical simulation the use of it as an ion trap was proved, and the structure optimization and electric field analysis was done, it has a better mass resolution than the triangular electrode ion trap based on the theoretical simulation.Chapter 6:Conclusions and prospects. In this chapter, achievements of this dissertation are concluded. At the same time, some drawbacks in our current researches are pointed out and corresponding methods for the improvement are also presented.