Enhanced Coverage and Sensitivity of Imprint DESI Mass Spectrometry Imaging for Plant Leaf Metabolites by Post-photoionization

Abstract

Plant metabolites exhibit a variety of different chemical properties, physiological activities, and biological functions. However, untargeted imaging of highly diverse metabolic profiles is still a great challenge. Here, metabolites in plant leaves were imaged via imprint, followed by desorption electrospray ionization/post-photoionization (imprint DESI/PI) mass spectrometry imaging. In contrast to the traditional imprint DESI method, quite a few metabolites, such as terpenoids, flavonoids, glycosides, alkylphenols, amino acids, phenolic acids, tannins, and lipids, in fresh sage leaves, ginkgo leaves, and tea leaves were well detected and imaged by imprint DESI/PI. More than 80 metabolites were additionally identified, and more than 1 order of magnitude higher signal intensities were obtained for most metabolites in the negative ion mode. By virtue of the significant improvement of coverage and sensitivity of PI, the catechin biosynthesis network in fresh tea leaves could be clearly illustrated, indicating the potential applicability of imprint DESI/PI in exploring the sites and pathways of plant metabolic conversion.

Lewis Acidic Metal–Organic Framework Assisted Ambient Liquid Extraction Mass Spectrometry Imaging for Enhancing the Coverage of Poorly Ionizable Lipids in Brain Tissue

“…In previous works, nanomaterial sheets were usually used to transfer targeted analytes from an uneven tissue surface to a flat surface without losing the spatial information, but the low imprinting efficiencies and delocalization are still issues needed to be addressed. , In this work, Zr 6 OTf-BTB sheets were prepared by a lamination technique. The mouse brain tissue slices were thaw-mounted onto the sheet.…”

“…Besides the above on-tissue reactions, imprinting techniques were also coupled with MSI to selectively transfer metabolites from tissues to adsorptive materials without losing spatial information. Imprinting materials porous polytetrafluoroethylene (PTFE), − aluminum foil TLC, electrospun nanofiber, and metal nanomaterials , had been successfully applied to imprint desorption electrospray ionization (DESI) and matrix-assisted laser desorption ionization (MALDI) MSI. However, novel nanomaterials with high surface area and highly selective surface interaction were seldom used in imprint MSI.…”

A Simple High-Flux Switchable VUV Lamp Based on an Electrodeless Fluorescent Lamp for SPI/PAI Mass Spectrometry

“…Single-photon photoionization (SPI) is one of the most popular soft ionization methods with great promise for advanced research . This ionization method exhibits many outstanding advantages, including high efficiency, limited fragmentation, simple mass spectrum interpretation, broad applicability for both polar and nonpolar compounds, and great tolerance of complex matrix components. − With the progress in mass spectrometry, SPI has been proven to have versatile applications, such as combination with liquid chromatography for measuring nonpolar compounds and coupling with laser desorption or desorption electrospray ionization as a postionization technique for mass spectrometric imaging and in situ analysis of biological samples. − In recent years, with the rapid development of SPI-mass spectrometry (SPI-MS) for the online detection of volatile organic compounds (VOCs), it has been widely applied in environmental analysis, − security checks, , process monitoring, , and breath-based health diagnosis. , …”

Noninvasive Detection of Skin Cancer by Imprint Desorption Electrospray Ionization Mass Spectrometry Imaging

“…MSI of molecule imprints has been reported as a powerful tool for extracting chemical information from many samples, including fungi, , bacteria, and plants. − This technique allows for the mapping of target molecules on the imprint rather than the sample itself. This greatly simplifies the sample preparation process.…”

“…This greatly simplifies the sample preparation process. Many materials have been shown to have the potential to transfer the chemical components from the sample, including PTFE, 18 TLC plates, 21 filter membranes, 20 and tapes. 16 As an imprint substrate for human skin, the material used should transfer as many molecules as possible and retain the original molecular pattern.…”