Research On Ion Transport Technology Based On Quadrupole-ion Trap Tandem Mass Spectrometer

In recent years,driven by the demand for analysis and technological development,mass spectrometry technology has developed rapidly.The performance of mass spectrometer with single mass analyzer cannot meet the needs,and tandem mass spectrometry has become a trend.By connecting quadrupole and linear ion trap in series,quadrupole-linear ion trap mass spectrometer combines the mass screening function of quadrupole with the storage function of ion trap which makes the analysis more efficient and accurate.In the mass spectrometer,the ion transport system plays an important role,which can efficiently transport ions to the mass analyzer.Because tandem mass spectrometry involves multiple analyzers,its ion transport system is often more complex,and the parameters that need to be adjusted also increase accordingly.If the parameter setting is unreasonable,it may directly lead to low transmission efficiency and even failure of detection.To solve these problems,the ion transport technology is studied on the platform of quadrupole-linear ion trap mass spectrometer.The quadrupole-linear ion trap mass spectrometer was built,according to the principle of tandem mass spectrometry instrument,the instrument components were selected,including ion source selection,vacuum system selection and ion transmission system components selection.After testing,the results were as follows:the mass scanning range of the instrument was 150-2022amu;reserpine（m/z 609.3）was screened by quadrupole,and the mass spectrum in the range of 606-612 amu was obtained,the half peak width of the mass spectrum peak was 0.7 amu,the resolution was good;by analyzing the full scan mass spectrum,the half-peak width of each mass spectrum peak in the mass scanning range of the instrument was obtained,and the ion trap resolution reached unit resolution.The automatic adjustment technology of ion transport system was studied.After combining the manual adjustment method and experience,the parameter automatic adjustment method was designed and the automatic adjustment process was confirmed.The software interface was designed,the strength calculation method was determined,the adjustment method was designed,the adjustment module was completed,and finally the automatic adjustment software was developed.After the completion of software development,reserpine was used for testing and automatic adjustment of parameters.The experimental results verified its feasibility.The realization of automatic adjustment software not only reduced the difficulty for the experimenters to adjust the instrument,but also saved a lot of adjustment time,helped experimenters obtain experimental information faster and more accurately,and was conducive to promoting the commercialization process of the instrument.Using the storage characteristics of ion guidance,the performance of the instrument can be improved.The conditions of ion guided ion storage were explored,and the DC capture voltage was studied.The guided storage method is realized by applying an appropriate DC capture voltage to lens which after guidance.Combining it with traditional ion storage methods,ion trap or ion guidance is used to store ions in different time sequences to realize coexistence method.Reserpine was used to test the methods,compared with the traditional ion storage method,the intensity change trend of the two methods is explored,and the feasibility of the coexistence method is verified.It is proved that this method can improve the ion utilization rate and improve the sensitivity of the instrument.