Solvent effects of N,N-dimethylformamide and methanol on mass spectrometry imaging by tapping-mode scanning probe electrospray ionization

Abstract

Mass spectrometry imaging (MSI) is an effective technique for visualizing the distribution of lipids in tissues. The direct extraction-ionization methods using minute volumes of solvent for local components have the...

Probe oscillation control in tapping-mode scanning probe electrospray ionization for stabilization of mass spectrometry imaging

“…We previously reported that a mixture of DMF and MeOH is appropriate for imaging lipids in mouse brain tissues. 23 Thus, we studied the A/P–D curves using a DMF/MeOH mixture. t-SPESI allows us to change the solvent composition, which can improve the selectivity and/or efficiency of the extraction–ionization of biological molecules.…”

“…A previously reported t-SPESI system was used. 23 A capillary probe was oscillated using a piezo actuator (PMF-3030, NTK Ceramic, Japan). The PMF-3030 is a small piezo actuator with a diameter of 7.3 mm and length of 17.2 mm, and is capable of providing a maximum displacement of 10 μm.…”

“…A program for varying the probe-sample distance was implemented in the t-SPESI system reported previously. 23 The distance between the probe and the sample was dynamically changed by applying a triangular voltage to the piezo Z-stage.…”

“…19 Tapping-mode scanning probe electrospray ionization (t-SPESI) extracts and ionizes molecules in tissue with a vertically oscillating capillary probe. [20][21][22][23] The probe oscillation is excited by a piezo actuator attached to the probe, through which a high-voltage solvent is continuously supplied. When the probe is in contact with the sample surface, a liquid bridge is formed between the probe and surface to induce liquid extraction of molecules from the sample.…”

DESI-MSI-guided exploration of metabolic-phenotypic relationships reveals a correlation between PI 38:3 and proliferating cells in clear cell renal cell carcinoma via single-section co-registration of multimodal imaging

“…Although DMF solvent mixtures yield spectra of relatively comparable quality, they favor low molecular mass compounds’ detection [ 4 ]. Moreover, due to its higher surface tension and boiling point compared to MeOH’s, DMF mixtures tend to produce larger spot sizes resulting in enlarged extraction areas and lower spatial image resolution, an effect that could be further intensified by the temperature functionality of the DESI XS system and HTL [ 4 , 13 , 21 ]. In this study case, we report a workflow that utilizes a single tissue section to obtain high molecular and phenotypical information, through multimodal imaging techniques, suitable for AI-enabled image analysis.…”