Development of a Miniature High Resolution Electron Impact Ion Source Time-of-Flight Mass Spectrometer

Since gas analysis mass spectrometers usually use quadrupole as the mass analyzer, the resolution is typically less than 300, and the same mass ions interference problem cannot be solved. This study developed a high resolution gas analysis mass spectrometer. Electron impact ion source reflection time-of-flight mass analyzer has been designed and tested. The length of vacuum chamber is only 45 cm. Mass resolution of 3,000 (Full width at half maximum, FWHM) has been achieved at m/z 28, as a result, CO and N-2 can be separated at the half peak height. The best resolution of instrument can reach 5000 (FWHM) at m/z 69. At the condition of direct ambient air sampling, Xe-136 (7.8 mu g/m(3)) and Kr-80 (2.8 mu g/m(3)) can be detected. The dynamic range is up to 106 with fast ADC acquiring system. This instrument can be used as a high-end gas mass spectrometer and applied to on-line gas analysis for process monitoring, environmental organic volatile compounds research, thermal analysis mass spectrometry and catalytic reaction monitoring.