Spectroscopy and Spectral Analysis, Volume. 39, Issue 5, 1354(2019)

Laser Desorption Time-of-Flight Mass Spectrometer for Sub-Micrometer-Scale Mass Spectrometry Imaging Using Near-Field Optics Technique

LI Xiao-ping*, YIN Zhi-bin, CHENG Xiao-ling, LIU Rong, and HANG Wei
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  • [in Chinese]
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    Laser-based ionization time-of-flight mass spectrometry techniques, as an emerging mass spectrometry imaging technique, has been widely used in material, geology, environment, pharmacology, and especially life science. However, it is difficult to achieve sub-micrometer-scale imaging resolution due to the limits of diffraction limit of light, focusing distance and numerical aperture of focusing lens. The introduction of the near-field optics technique has overcome this limitation. By combining the near-field optics technique and laser ionization mass spectrometry, nanoscale crater on the solid surface could be achieved. In addition, traditional mass spectrometry imaging techniques usually neglect the topographical information of the irregular sample surface and cause unreal imaging. So it is important for multifunctional in-situ characterization to get the chemical and topographical information simultaneously. In this paper, a near-field nanometer aperture tip desorption postionization time-of-flight mass spectrometer was developed for sub-micrometer-scale chemical and topographical analysis. 532 and 355 nm laser were used as the desorption and postionizationlaser respectively. A tuning fork based AFM system was used to control the distance between the tip and sample. Copper phthalocyanine molecular layers was ablated to produce a series of nanoscale craters with the size from 550 to 850 nm, which indicated that the technique could achieve sub-micrometer-scale lateral resolution. Furthermore, a mass spectrometry imaging with high lateral resolution was carried out on a 7.5 μm×7.5 μm copper phthalocyanine grid pattern sample. As the results showed, the chemical imaging of the sample surface was achieved simultaneously with the topographical information, expanding the in-situ characterization ability of the mass spectrometry imaging techniques.

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    LI Xiao-ping, YIN Zhi-bin, CHENG Xiao-ling, LIU Rong, HANG Wei. Laser Desorption Time-of-Flight Mass Spectrometer for Sub-Micrometer-Scale Mass Spectrometry Imaging Using Near-Field Optics Technique[J]. Spectroscopy and Spectral Analysis, 2019, 39(5): 1354

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    Paper Information

    Received: Jan. 22, 2019

    Accepted: --

    Published Online: May. 13, 2019

    The Author Email: Xiao-ping LI (xinyuxin150@163.com)

    DOI:10.3964/j.issn.1000-0593(2019)05-1354-05

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