Research And Development Of Control System For Triple Quadrupole Mass Spectrometer

In recent years,mass spectrometry has become the powerful analytical and detection technology in the field of chemistry and life sciences due to its rapid analytical capabilities.And triple quadrupole mass spectrometry(QqQ-MS)is becoming an important tool for food safety and clinical detection.The triple quadrupole mass spectrometer control system was studied in this paper,which would be conducive to improving the situation that China QqQ-MS is over-reliant on foreign imports.Based on the single quadrupole scanning theory,the working principle and control method of each quadrupole in the multiple modes of ion scan of triple quadrupole were studied.According to quadrupole size parameters,the calculation model of the quadrupole mass scanning voltage parameters was established,and then verified by Simion.Aiming at the optimization of multi-lens voltage parameters,particle swarm optimization algorithm combined with Simion simulation software was used for the first time.The optimized ion transfer efficiency is 0.22%,which can be used to guide the actual lens voltage parameters debugging.Based on the analysis of the QqQ-MS instrument system principle and circuit,the software and hardware requirements of the control system were analyzed and sorted out,and the control schemes of quadrupole mass scanning and calibration,vacuum and gas flow were designed.The lens and RF power supply system are controlled by 16-bit high-precision DA chip.Through unit testing,the drive voltage control accuracy reached 76 uV,and the 3 mV voltage switching time of RF power supply was 10 us.When the mass changes by 100 amu,that is,the voltage change is about 122 mV,the power supply stabilization time is about 800 us.At present,the control system of the triple quadrupole mass spectrometer prototype has been completed.The QqQ-MS control system based on the NI virtual instrument platform was developed to realize the functions such as multiple modes of ion scan,mass axis and resolution correction,ion signal acquisition and storage,automatic vacuum pumping,constant temperature heating of ion source,gas flow control and so on.Through the detection of PPG standard samples,the mass axis correction was relatively accurate,and the mass resolution reached 0.1 amu,which can be used to detect organic sample.The ion source temperature was adjusted by incremental PID algorithm and the temperature control accuracy is 0.12?.Finally,in order to solve the ion crosstalk problem,the voltage switching time was optimized to 5 ms.The development of QqQ-MS control system based on LabVIEW will provide a very favorable technical parameter support for the subsequent development of embedded systems.