Mapping metabolites from rough terrain: laser ablation electrospray ionization on non-flat samples

Abstract

Established laser-based ionization experiments require the surface of a sample to be as flat as possible to guarantee optimal laser focus. A laser ablation electrospray ionization (LAESI) source was custom-built to accommodate the topography of non-flat sample surfaces. Employing a confocal distance sensor, a height profile of the surface in question was recorded prior to the actual ionization experiment. The robustness of the system was evaluated by the metabolic profiling of radish (Raphanus sativus) leaves, chosen due to their pronounced surface features and known content of specialized metabolites. After the ionization experiments, light microscopy imaging was performed to evaluate ablation crater size and position. Reproducible ablation mark diameters of 69 7 mm in average have been achieved. Mass spectrometric imaging capability has been proven on R. sativus leaf samples as well

Mass Spectrometry Imaging: A Review of Emerging Advancements and Future Insights

“…These m/z distributions were acquired in the same experiment as the topographical profile. Reproduced from Bartels, B.; Kulkarni, P.; Danz, N.; Bocker, S.; Saluz, H. P.; Svatos, A., RSC Advances 2017 , 7 (15), 9045-9050 (ref 92), with permission (https://creativecommons.org/licenses/by/3.0/) of the Royal Society of Chemistry.…”

In situergot alkaloid detection in threeBalansia epichloe-infected grass species

“…; Shestha and Vertes ; Bartels et al . ). Furthermore, LAESI–mass spectrometry procedures allow for the noninvasive measurement and chemical analyses of microbes–host parasitic interactions during host development and manipulations.…”

“…A method that eliminates extensive sample preparations, including numerous fermentations, extractions, thin-layer and liquid chromatography is needed to screen endophyte-infected pasture grasses for the presence of ergot alkaloid. Laser ablation electrospray ionization (LAESI)-mass spectrometry is a recently developed procedure capable of the in situ detection of microgram levels of metabolites in plant and animal tissues (Nemes and Vertes 2007;Nemes et al 2008;Shestha and Vertes 2009;Bartels et al 2017). Furthermore, LAESI-mass spectrometry procedures allow for the noninvasive measurement and chemical analyses of microbes-host parasitic interactions during host development and manipulations.…”

An approach for visualizing the spatial metabolome of an entire plant root system inspired by the Swiss‐rolling technique

“…Matrix‐assisted laser desorption/ionization (MALDI)‐MSI was previously utilized to visualize rhizobacteria‐legume metabolite exchange related to nitrogen fixation within Medicago and soybean root nodules, for example. MALDI‐like techniques using near‐infrared lasers (ie, 2940 nm), which couple directly into O―H vibrational bands of water, permit water to be used as the desorption matrix, and these sources can be used to spatially probe and image living plant tissue using mass spectrometry . The use of MSI and other similar tools is expected to expand in analyzing root systems.…”