Unexpected matrix interactions in liquid secondary ion mass spectrometry of two pyranosyl mercaptans

Abstract

An unexpected interaction with a thioglycerol matrix appeared in the liquid secondary ion mass spectrometry (LSIMS) spectra of two pyranosyl mercaptans [2,3,4,6-tetra-O-acetyl-1-thio-β-D-glucopyranose (1a) and 2,3,4,6-tetra-O-acetyl-1,5-dithio-β-D-glucopyranose (1b)] often used to prepare glucosinolates, important thiosaccharidic metabolites found in all plants of the order Brassicales. The reactions, probably occurring in the solvent cage, seem to involve radical mechanisms.

A Green Approach to the Production of Hybrid Diindolylmethane‐Phenylboronic Acids via a 3MCR: Promising Antineoplasic Molecules

“…Several attempts to determine the expected molecular ions of the target molecules 5-7 using EI, CI, and FAB + (glycerol, m-nitrobenzylalcohol, and ooctyloxynitrobenzene) were unsuccessful; however, common and appropriate fragmentation patterns were detected, as mentioned in the experimental section. Therefore, due to our recent knowledge that the thioglycerol matrix could yield interesting interactions [47,48], we considered that the sulfur atom inside the matrix could produce artifacts by means of a Lewis interaction, with the empty orbital of the boron atom in the molecules of interest (sometimes known as quasimolecular ions). Consequently, the predicted structures were unequivocally confirmed by obtaining the elemental compositions using high resolution mass spectrometry, as shown in Figure 3.…”

Thioglycerol matrix interactions in the positive ion fast atom bombardment mass spectrometry of several Hantzsch and Biginelli ester derivatives of boronic acids

“…The expected molecular or [M+H] + ions of the target molecules 5a‐c , 6a‐c , 7b‐c and 9a‐c were not obtained using electron ionization, chemical ionization, or FAB + (with glycerol, m ‐nitrobenzyl alcohol, or o ‐octyloxynitrobenzene matrices). Therefore, as it is known that the thioglycerol (TG) matrix affords interesting interactions, it was considered that the sulphur atom, by means of Lewis interaction inside the matrix with the empty orbital of the target BCC, could produce FAB adducts related to the target molecules.…”

“…Soft mass spectrometry (MS) ionization modes are particularly useful for analyzing non‐volatile or thermolabile compounds. In the Fast Atom Bombardment (FAB) ionization mode the sample is suspended in a non‐volatile liquid matrix, and, in positive ion FAB, an [M+H] + ion is usually produced, allowing the molecular mass of the target molecule to be determined. However, anomalous artifact ions sometimes appear in the FAB spectrum: derived from processes such as solvent condensation, ligand exchange, dehalogenation, hydride abstraction, and adducts due to abrupt changes in surface tension in the region of bombardment, as well as from convective and diffusive processes .…”