Development and Engineering of Miniature Ion Trap Mass Spectrometer

Traditional large mass spectrometer has the advantages of high sensitivity and fast speed of analysis. However, because of its large size, it only can be used in professional labs generally. The miniature mass spectrometer has the advantages of lightweight and portable. Although some performances are sacrificed, the needs of the application field of on-site detection were met. The ion trap was used as the mass analyzer for miniature mass spectrometer, because of its good performance and small size. In this paper, two miniature mass spectrometers called “Brick-L” and “Brick-V” were introduced, which were based on the new technologies developed by our lab, including the quadrupole enhanced dipolar resonance ejection from the linear ion trap, the continuous atmospheric pressure interface, and the hybrid ion funnel. Both the miniature mass spectrometers had similar vacuum chamber structures and the same main components, such as ion funnel, mass analyzer and control circuit. The switch between Brick-V and Brick-L could be achieved by simply changing the front board of the chamber where the interface system is located, and it allowed the instruments to meet variable demands of on-site detection more easily. The difference was that the Brick-L required to be coupled with an atmospheric pressure ion source, and it could detect gas, liquid and solid samples. An UV lamp ion source was installed inside the Brick-V, which could detect volatile organic compounds (VOCs). The overall weight of the miniature mass spectrometers is about 20 kg, the size is 38 cm×23 cm×34 cm, the power consumption is 200 W, and they have the capability of MS². The limits of detection (LODs) of cocaine and imatinib can reach 1 μg/L for Brick-L, and the resolution is more than 1 600. Brick-V can be used to identify fruits. Due to use the continuous atmospheric pressure interface, Brick-V has more resistant to pollution and shorter detection cycle time than the same type of miniature mass spectrometer using the photon ionization source. The two instruments are portable and easy to operate, which can be used in rapid on-site analysis and have good application prospects.