Utilisation of Gas-Phase Ion—Molecule Reactions for Differentiation between Phospho- and Sulfocarbohydrates

Abstract

Gas-phase ion-molecule reactions of four boron-containing neutrals were explored as a means for differentiation between isobaric phospho- and sulfocarbohydrates. Phosphorylation and sulfation impose an addition of 80 Da to the molecular mass, so for low-resolution mass spectrometers compounds that have such modifications will appear at the same nominal mass-to-charge (m/z) ratio. However, the ions of these isobaric species behave differently in ion-molecule reactions. All four evaluated neutral molecules [trimethyl borate (TMB), triethyl borate (TEB), diethylmethoxyborane (DEMB) and diisopropoxymethylborane (DIPMB)] proved to be reactive towards phosphorylated sugars and unreactive towards sulfated carbohydrates. In addition, TMB and TEB were found suitable for distinguishing positional isomers of phosphorylated carbohydrates, while reactions with DEMB and DIPMB were successful in differentiating phosphorylated, sulfated and unmodified deprotonated sugars. Similar reactions in the positive ion mode (alkali cationised) were found to be less conclusive.

Identification of the Phenol Functionality in Deprotonated Monomeric and Dimeric Lignin Degradation Products via Tandem Mass Spectrometry Based on Ion–Molecule Reactions with Diethylmethoxyborane

“…However, most studies on functional group-specific ion-molecule reactions have focused on protonated analytes. Only in a few cases were deprotonated analytes examined [24][25][26][27][28], and to the best of our knowledge, no reagents have been developed for the identification of the phenol functionality. In this study, diethyl methoxyborane (DEMB) is explored as a reagent for the identification of the phenol functionality in deprotonated ligninrelated analytes.…”

“…In this study, diethyl methoxyborane (DEMB) is explored as a reagent for the identification of the phenol functionality in deprotonated ligninrelated analytes. DEMB is known to react with negative ions and has been shown to allow differentiation of isobaric ions (deprotonated phosphorus-and sulfocarbohydrates) [25].…”

Evaluation of Various Silicon- and Boron-Containing Compounds for the Detection of Phosphorylation in Peptides via Gas-Phase Ion-Molecule Reactions

“…IMRs of phosphorylated peptides with TEB proceed quite similarly to TMB reactions [ Figure 1(a) shows an example of ALsR] that we reported previously. 29 Primarily, products of such reaction will appear at m/z values that correspond to the addition of 100 Da [ Figure 1(b)] to the parent ion, which corresponds to the complex ion that lost one ethanol molecule (Scheme 1). Although no collisional activation was applied to drive this reaction, the nearly thermal (as shown by Gronert 31 ) ions in IMRs in the ion trap possess sufficient energy to overcome activation barriers as high as 117 kJ mol -1 .…”

“…Earlier, we expanded Gronert's approach to detect phosphopeptides selectively in the mixture using a LC-IMR-MS interface on the QIT instrument 28 utilizing a TMB neutral reagent. More recently, we explored reactions of phospho-and sulfocarbohydrates with various boron-containing neutral reagents 29 and found that some of them may offer advantages over TMB in specific applications. Hence in this work we expanded our research to a series of boron-and silicon-containing neutral compounds: TMB, diethylmethoxyborane (DEMB), triethyl borate (TEB), diisopropoxymethylborane (DiPMB), chlorotrimethylsilane (TMSCl), and N,O-bis(trimethylsilyl)acetamide (TMSA).…”

Integration of a Multichannel Pulsed-Valve Inlet System to a Linear Quadrupole Ion Trap Mass Spectrometer for the Rapid Consecutive Introduction of Nine Reagents for Diagnostic Ion/Molecule Reactions

“…Gas-phase ion/molecule reactions have been used extensively in the past to probe the structures of organic compounds and biomolecules. − Diagnostic reactions have been developed for the identification of many functional groups, including amido, carboxylic acid, , epoxide, N -oxide, ,− sulfone, ,, and sulfoxide functionalities. , Further, isomeric compounds, such as primary, secondary, and tertiary amines, can be differentiated with gas-phase ion/molecule reactions.…”