On‐tissue chemical derivatization reagents for matrix‐assisted laser desorption/ionization mass spectrometry imaging

Abstract

Matrix-assisted laser desorption/ionization mass spectrometry imaging (MALDI MSI) is a key tool for the analysis of biological tissues. It provides spatial and quantitative information about different types of analytes within tissue sections. Despite the increasing improvements of this technique, the low detection sensitivity of some compounds remains an important challenge to overcome. Poor sensitivity is related to weak ionization efficiency, low abundance of analytes and matrix ions, or endogenous interferences. On-tissue chemical derivatization (OTCD) has proven to be an important solution to these issues and is increasingly employed in MALDI MSI studies. OTCD reagents, synthesized or commercially available, have been essentially used for the detection of small exogenous or endogenous molecules within tissues. Optimally, an OTCD reaction is performed in mild conditions, in an acceptable range of time, preserves the integrity of the tissues, and prevents the delocalization. In addition to their reactivity with a targeted chemical function, some OTCD reagents can also be used as a matrix, which simplifies the sample preparation procedure. In this review, we present an exhaustive overview of OTCD reagents and methods used in MALDI MSI studies.

Pyrylium-Based Derivatization for Rapid Labeling and Enhanced Detection of Cholesterol in Mass Spectrometry Imaging

“…The reaction method we developed supports a fast and stable reaction (Figure S5c). While the preprocessing is carried out in two steps, it is simple and easy to operate, avoiding undesired changes occurred in those complex processing process. ,, We further applied five kinds of derivatization reagents to the detection of standard products to screen out the most suitable derivatization reagent in MALDI-MS. As shown in Figure c, CTMP and CDMP have higher carboxyl activity, and their derivatives are easier to detect compared to other types. Although the corresponding derivatives of CTPP, CMPP, and CFPP are dominant in UV absorption, the fused ring excessively disperses the activation effect of the positive charge on the carboxyl group, which leads to their undesirable mass spectral response.…”

Mass Spectrometry Imaging Techniques Enabling Visualization of Lipid Isomers in Biological Tissues

“…Chemical derivatization becomes popular in MSI as it brings enhanced detection of otherwise undetectable or less abundant species . In lipid isomer analysis, the derivatization is focused mainly on the electron-rich CC susceptible to the attack of electrophiles or radicals.…”

Tissue sample preparations for preclinical research determined by molecular imaging mass spectrometry using matrix‐assisted laser desorption/ionization

“…Therefore, molecular imaging by MS (IMS) is one of the techniques that allow for the simultaneous analysis of thousands of analytes and can profile various types of molecules -metabolites, drugs, peptides, and proteins. The obtained profiles can be related to histopathological stains [1,2,[7][8][9][10][11] The first application of IMS was reported in the 1960s. It was caused by the introduction of secondary IMS (SIMS).…”