Discontinuous Atmospheric Pressure Interface in-Trap Single Photon Ionization Ion Trap Mass Spectrometry (DAPI in-Trap SPI ITMS)

Abstract

A compact in-trap single photon ionization (SPI) system, termed discontinuous atmospheric pressure interface (DAPI) ion trap mass spectrometry (ITMS), for the rapid determination of trace volatile organic compounds (VOCs). DAPI enables the maintenance of high analyte pressure in the SPI source while preserving the vacuum. Utilizing vacuum ultraviolet (VUV) lamp as the ion source, we ionize the analyte within an enclosed miniature 3D ion trap for efficient analysis. Experimental findings demonstrate that the system achieves a mass resolution of less than 0.5 atomic mass units for full width at half maxima (FWHM), providing unit resolution. For the response for benzene, the system achieves almost instantaneous response, with rise and fall times of only 2 s, which is a significant advantage compared to the membrane inlet (MI) approach necessary for on-site detection. Additionally, tandem mass spectrometry (MS/MS) with unit m/z isolation window was achieved and resolved dimethyl disulfide and phenol with similar molecular weights. Our results demonstrate that the system provides excellent performance and we anticipate its application in rapidly determining VOCs.

Keywords:

• Miniature mass spectrometry
• rapid on-site detection
• single photon ionization (SPI)
• tandem mass spectrometry (MS/MS)
• volatile organic compounds (VOCs)

Disclosure statement

No conflicts of interest are reported by the authors.

Additional information

Funding

This work was supported by the National Natural Science Foundation of China [U20A20121], National Key Research and Development Program [2023YFC3304203], Yangtze River Delta Science and Technology Innovation Community Joint Research Project [2023CSJGG1800], the Key Research and Development Program of Zhejiang Province [2020C03064, 2024C03266 and 2024C03101], the Natural Science Foundation of Zhejiang Province [LY22F010004 and LGC22B050002] and the Ningbo Science and Technology Project [2022Z241, 2023Z132, 2023Z168 and 2023S151].