All these and other comfortable experiences in daily life are inseparable from the contribution of vacuum. EVP vacuum provides essential and comprehensive solutions for the production of these products. Our high-performance product portfolio covers everything from vacuum pumps to measurement and analysis equipment to a complete vacuum system. Mass spectrometer is a kind of precise and efficient multi-functional analytical instrument, which can separate molecules with different molecular weight according to the different m / Z ratio of ions, determine the molecular weight and analyze the composition and structure. This paper intends to analyze the application of vacuum system in mass spectrometer.
Mass spectrometer generally includes sample injection system, ion source, mass analyzer, ion detector, vacuum system and data processing system.
Precautions for mass spectrometer:
1. The vacuum of mass spectrometer shall not be too low. Too low can cause:
1) a large amount of oxygen will burn the filament of the ion source;
2) additional ion molecule reactions are induced, which complicates the analysis of MS;
3) it may cause discharge between electrodes in the analysis system;
4) it will increase the background.
2. The mass spectrometer has its own magnetic field and is sensitive to external magnetic field, so do not bring in magnetic field or move it during maintenance, especially do not have any impact on the magnet.
3. Due to the high vacuum requirements of the ionization chamber, in addition to the operation of the mechanical vacuum pump, the mass spectrometer is also designed with a molecular pump, so the mechanical vacuum pump must be kept in working condition during non working hours.
4. The mass spectrometer has high requirements for the working environment, so there must be air conditioning in the room and keep indoor ventilation.
5. In order to ensure the normal operation of the machine, the purity of carrier gas (he) must be over 99.99%.
6. Before replacing the filament, the mechanical vacuum pump must be turned off. When the normal pressure is restored, the machine will be dismantled. If the power supply is cut off, the mechanical vacuum pump must be turned on to the normal state for more than 24 hours before normal detection.
Main applications of mass spectrometer:
1. Fermentation reaction
2. Fuel cell research
3. Catalytic reaction
4. Semiconductor Exhaust Monitoring
5. Gas monitoring
6. Mixed gas detection
7. Vacuum equipment monitoring
8. Detection after drying of dispensing solvent
9. Gas output rate of gas scrubber
10. CVD (chemical vapor deposition)
11. thermal analysis
12. Reaction process monitoring
13. Program temperature desorption experiment
14. Vehicle exhaust detection
15. Battery production
16. Transformer oil analysis
17. Drug packaging test
The working principle of the vacuum system is to start the system, the main vacuum pump group starts to work until the vacuum degree in the vacuum tank reaches the set upper limit value, the vacuum pump automatically stops running, and the vacuum in the central vacuum system is maintained by the vacuum check valve on the pipeline. If the vacuum degree in the vacuum tank drops and is lower than the set lower limit value due to work demand, the standby vacuum pump group will start automatically. Thus, the vacuum degree of the vacuum system can maintain a stable vacuum source and meet the production requirements.
The application of the vacuum system in the mass spectrometer is to prevent its vacuum from being too low. All areas with sample molecules and ions in the mass spectrometer must be in a vacuum state, so as to reduce the background and interference caused by the collision between ions or between ions and molecules, and the oxygen in the residual air will burn the filament of the ion source.