R & D, Based On The Printed Circuit Board (pcb), Rit And The Array Of Ion Trap Mass Spectrometer

Mass spectrometry provides high sensitivity for the analysis and identification ofunknown compounds,and it has become one of the most widely used analyticaltechnique in modern science.Mass spectrum data is absolutely necessary in manyinternational accepted analytical standards.At the present time,mass spectrometer hasbecome indispensable analytical instrument in many areas.Furthermore,massspectrometer plays an increasingly important role in hot-spot fields such as drugdiscovery,life science,environmental protection,food safety,Determination of illicitdrugs,public safety,aerospace and military technique,etc.Although mass spectrometer has made great successes in many analytical fields,it also has some disadvantages.Firstly,most commercialized mass spectrometers havedisadvantages of large size,weight,high price and complexity of maintenance.Alarge mass spectrometer usually costs several million dollars,which prevents furtherextension of areas of application of mass spectrometers.Secondly,the analyticalefficiency of most mass spectrometers today is hard to meet the requirement of manyareas which have large mount of samples to be analyzed,especially such areas as drugdiscovery and biology.Many drug developing factories have to equip scores or evenhundreds of mass spectrometers,which causes the high price of new drug.Therefore,the major developing directions of mass spectrometer can be summarized to twopoints:(1)low cost and miniaturization;(2)high-throughput mass analysis.With the rapid development of China's economy,the requirements for massspectrometers are becoming more and more large.Unfortunately,except for a smallnumber of low-performance mass spectrometers,the Chinese market of massspectrometer is completely occupied by foreign products.According to estimations byrelevant experts,China will spend 5 billion yuan to buy foreign mass spectrometers in2010.However,more mass spectrometers are still needed to meet the requirements ofanalytical fields in China.Obviously,it is urgent for us to develop our own massspectrometers.Recent years,the Chinese government started to encourage theresearch and development of mass spectrometer.During National Key TechnologyR&D Program in the 10th Five year Plan of china,the program entitled as"Development of chromatograph-mass spectrometer"were supported by the government.At the same time,more and more scientists in China started to devotethemselves to the research and development of mass spectrometers.Till now,someprogresses have been made in development of quadrupole mass filter,rectilinear iontrap mass spectrometer and gas chromatograph-mass spectrometer (GC-MS),etc.However,lack of key technology and intellectual property fights is still a seriousproblem in the field of developing mass spectrometer.We proposed novel methods of building low-cost mass spectrometers andhigh-throughput mass spectrometers base on the evaluation of internationaldeveloping direction of mass spectrometer and current situation in China.The majorcontribution and innovation of this thesis are:(1)A novel mass analyzer,called iontrap array (ITA)mass analyzer,which can be used for high-throughput mass analysis,was designed with full intellectual property rights.(2)The normal printed circuitboard (PCB)material and technology were used to fabricate ion trap mass analyzer,and so reduces the cost of building the ion trap mass spectrometer.(3)The digital iontrap technique,which was invented in recent years,was applied to the rectilinear iontrap and ITA mass spectrometers to improve their analytical performance such asmass range and mass resolution..The whole thesis is divided into six chapters,and its major contents are listed asfollows:Chapter 1:Introduction.Firstly,we summarized the principle and history of massspectrometry,evaluated the current situation in the field of mass spectrometry,andpointed out that the developing directions of mass spectrometer are low-cost,miniaturization and high-throughput mass analysis.Secondly,we introduced thespecifications,types and basic theory of ion trap,and explained why the ion trap massanalyzer has its own advantages for building miniaturized and low-cost massspectrometer.Lastly,we proposed our researching methods and purpose based on theconsiderations and summarizations mentioned above.Chapter 2:The development of PCB ion trap mass spectrometer coupled with anelectron impact (EI)ion source.The rectilinear ion trap is structure-simplified linearion trap.At present,the rectilinear ion trap was almost fabricated based on stainlesssteel and precise mechanical fabrication technology,and so it still has relatively highcost.We proposed a novel method of constructing the rectilinear ion trap based onPCB material and fabrication technology.The PCB ion trap has very low cost andsimple structure.The process of building the PCB ion trap and the calculation and analysis of electric fields inside it are described in this chapter.We also built a PCBion trap mass spectrometer coupled with an EI source to test its analyticalperformance.Experiments show that the mass spectrometer has a mass resolution inexcess of 400 and a mass range of over 300 Thomson.The PCB ion trap could alsoperform functions of mass-selection ion isolation and mass-selected ion ejection.Chapter 3:The development of PCB ion trap mass spectrometer coupled with anelectrospray ion (ESI)source.To improve the performance of PCB ion trap,weintroduced electrospray ion source and digital ion trap technique to build the ESI-PCBion trap mass spectrometer.The process of designing the instrument,including theconstruction of three-stage vacuum system,the design of digital electronic system andthe construction of the ESI source,are described detailedly in this chapter.Experiments show that a mass range in excess of 2600 Thomson and a massresolution over 500 were achieved in the instrument.During the experiment,we useda digital trapping waveform with amplitude (V_0-p)of only 200 V to drive the PCB iontrap,therefore,its mass range could be further extended by increasing the amplitudeof digital trapping waveform,which makes it possible to apply the PCB ion trap inlarge molecule analytical fields such as life science and proteomics.Chapter 4:The design and development of PCB ion trap array (ITA)massspectrometer.In this chapter,we introduced the process of designing the ITA massanalyzer and its basic principle.An ITA mass analyzer consists of only one pair ofPCB electrodes and two pairs of rectangular electrodes made of stainless steel,and ithas very simple structure and very low cost.However,the ITA is a powerful massanalyzer,for it has multiple mass analysis channels,and each channel has thefunctions of a conventional ion trap,such as ion storage,mass analysis,mass-selectedion isolation and mass-selected ion ejection.A PCB-ITA mass spectrometer was alsobuilt to test its performance.A mass resolution in excess of 1300 and a mass rangeover 500 Thomson were achieved experimentally in the instrument.Furthermore,wegot mass spectrum in different channels of the ITA,which indicates that the ITA massanalyzer has ability of performing high-throughput mass analysis.Chapter 5:Geometrical optimization of ITA mass analyzer.The analyticalperformance of any ion trap is determined by the electric fields inside it,and electricfields are affected directly by the geometrical structure and dimensions of the ion trap.The geometrical dimensions of the ITA mass analyzer were optimized in computersimulation and experiments.First,we construct computer models of different ITA mass analyzers with different dimensions,and calculated relevant electric fields insidethem.Then,we simulated mass resolution of different ITA mass analyzers.Iontrajectories were also simulated.At last,we constructed 4 ITA mass analyzers withdifferent dimensions and tested their mass resolution respectively.The experimentresults are accordance with the simulation results.Chapter 6:Conclusion and prospect.In this chapter,achievements of thisdissertation were concluded.At the same time,some drawbacks in our currentresearches were pointed out and corresponding methods for the improvement werealso presented.