Formation of [M + 15]+ ions from aromatic aldehydes by use of methanol: in-source aldolization reaction in electrospray ionization mass spectrometry

Wang, Lin; Chai, Yunfeng; Tu, Peijun; Sun, Cuirong; Pan, Yuanjiang

doi:10.1002/jms.1994

Cited by 20 publications

(26 citation statements)

References 28 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The (M þ 15) þ ion is possibly an oxocarbenium ion formed in a reaction with methanol in the ionization process as has been reported previously for aromatic aldehydes. 18 In CID, fragmentation around the ester moiety was observed, identical to BO ( Supplementary Fig. S2C).…”

Section: Liquid Chromatography-mass Spectrometrymentioning

confidence: 89%

The Effect of Ambient Ozone on Unsaturated Tear Film Wax Esters

Paananen

Rantamäki

Parshintsev

et al. 2015

Invest. Ophthalmol. Vis. Sci.

View full text Add to dashboard Cite

Citation: Paananen RO, Rantamäki AH, Parshintsev J, Holopainen JM. The effect of ambient ozone on unsaturated tear film wax esters. Invest Ophthalmol Vis Sci. 2015;56:8054-8062. DOI:10.1167/iovs.15-18398 PURPOSE. Tear film lipid layer (TFLL) is constantly exposed to reactive ozone in the surrounding air, which may have detrimental effects on ocular health. Behenyl oleate (BO), a representative tear film wax ester, was used to study the reaction with ozone at the air-water interface.METHODS. Time-dependent changes in mean molecular area of BO monolayers were measured at different ozone concentrations and surface pressures. In addition, the effect of ascorbic acid on the reaction rate was determined. Reaction was followed using thin-layer chromatography and reaction products were identified using liquid chromatographyelectrospray ionization mass spectrometry (LC-MS). Tear fluid samples from healthy subjects were analyzed with LC-MS for any ozonolysis reaction products. RESULTS.Behenyl oleate was found to undergo rapid ozonolysis at the air-water interface at normal indoor ozone concentrations. The reaction was observed as an initial expansion followed by a contraction of the film area. Ascorbic acid was found to decrease the rate of ozonolysis. Main reaction products were identified as behenyl 9-oxononanoate and behenyl 8-(5-octyl-1,2,4-trioxolan-3-yl)octanoate. Similar ozonolysis products were not detected in the tear fluid samples.CONCLUSIONS. At the air-water interface, unsaturated wax esters react readily with ozone in ambient air. However, no signs of ozonolysis products were found in the tear fluid. This is most likely due to the antioxidant systems present in tear fluid. Last, the results show that ozonolysis needs to be controlled in future surface chemistry studies on tear film lipids.

show abstract

Section: Liquid Chromatography-mass Spectrometrymentioning

confidence: 89%

The Effect of Ambient Ozone on Unsaturated Tear Film Wax Esters

Paananen

Rantamäki

Parshintsev

et al. 2015

Invest. Ophthalmol. Vis. Sci.

View full text Add to dashboard Cite

show abstract

“…Finally, stable covalent adduct ions may dissociate at higher cone voltage from the ionized incorporated group or from another group of atoms if fast proton migration can occur. Other stepwise processes may also occur such as addition/elimination‐like reaction, eg, the methylation of protonated aromatic aldehydes (or more likely their hydrogen bonded adduct ions) by nucleophilic attack of methanol used as a solvent that results in a covalent adduct ion [M + CH 3 OH 2 ] + consecutively followed by the loss of water yielding [(M + CH 3 OH 2 ) − H 2 O] + as illustrated in Figure . In the later example, the ion/molecule reaction gives rise to an MS signal +14.0156 m/z distant from the protonated molecule [M + H] + peak, which could also be noted [(M + H) + CH 2 app ] + rather than [M + 15] + .…”

Section: Illustrative Examples and Discussionmentioning

confidence: 99%

“…Illustration of an ion/molecule reaction giving an unexpected product ion (m/z corresponds to the accurate mass of M + 15 Da) [Colour figure can be viewed at wileyonlinelibrary.com]…”

Section: Illustrative Examples and Discussionmentioning

confidence: 99%

Proposal for a chemically consistent way to annotate ions arising from the analysis of reference compounds under ESI conditions: A prerequisite to proper mass spectral database constitution in metabolomics

et al. 2019

View full text Add to dashboard Cite

Nowadays, high‐resolution mass spectrometry is widely used for metabolomic studies. Thanks to its high sensitivity, it enables the detection of a large range of metabolites. In metabolomics, the continuous quest for a metabolite identification as complete and accurate as possible has led during the last decade to an ever increasing development of public MS databases (including LC‐MS data) concomitantly with bioinformatic tool expansion. To facilitate the annotation process of MS profiles obtained from biological samples, but also to ease data sharing, exchange, and exploitation, the standardization and harmonization of the way to describe and annotate mass spectra seemed crucial to us. Indeed, under electrospray (ESI) conditions, a single metabolite does not produce a unique ion corresponding to its protonated or deprotonated form but could lead to a complex mixture of signals. These MS signals result from the existence of different natural isotopologues of the same compound and also to the potential formation of adduct ions, homomultimeric and heteromultimeric ions, fragment ions resulting from “prompt” in‐source dissociations. As a joint reflection process within the French Infrastructure for Metabolomics and Fluxomics (MetaboHUB) and with the purpose of developing a robust and exchangeable annotated MS database made from pure reference compounds (chemical standards) analysis, it appeared to us that giving the metabolomics community some clues to standardize and unambiguously annotate each MS feature was a prerequisite to data entry and further efficient querying of the mass spectral database. The use of a harmonized notation is also mandatory for interlaboratory MS data exchange. Additionally, thorough description of the variety of MS signals arising from the analysis of a unique metabolite might provide greater confidence on its annotation.

show abstract

“…When analyzing enaminones in ESI positive mode, pyrazoles are formed by reacting with acetonitrile in the presence of copper acetate . The [M + 15] + ion was observed as the most abundant ion when measuring aromatic aldehydes due to the gas phase in‐source aldolization reaction . Other side reactions, occurred during the ionization process, such as redox, fast dimerization reaction, and oxygen addition, were also observed using ESI as the ionization method.…”

Section: Introductionmentioning

confidence: 99%

Gas phase reaction between chromones and solvent in an electrospray ionization source

et al. 2018

Self Cite

View full text Add to dashboard Cite

Chromones were measured by using electrospray ionization mass spectrometry in negative mode. Interestingly, in addition to the deprotonated ion ([M − H]−), unexpected [M + 17]− and [M + 31]− ions were observed in high intensity when water and methanol were used as the solvent. Chromones with different substitutes were tested. Compared with the deprotonated ion, [M + 17]− and [M + 31]− ions were observed with higher abundances when the C‐3 site of chromones was substituted by electron withdrawing groups. Based on high performance liquid chromatography‐mass spectrometry (LC‐MS), deuterium‐labeling and collisional‐induced dissociation experiments, a covalent gas‐phase nucleophilic addition reaction between chromone and water, and the formation of a noncovalent complex between chromone and methanol were proposed as the mechanism for the observed [M + 17]− and [M + 31]− ions, respectively. Understanding and using these unique gas phase reactions can avoid misannotation when analyzing chromones and their metabolites.

show abstract

Formation of [M + 15]+ ions from aromatic aldehydes by use of methanol: in-source aldolization reaction in electrospray ionization mass spectrometry

Cited by 20 publications

References 28 publications

The Effect of Ambient Ozone on Unsaturated Tear Film Wax Esters

The Effect of Ambient Ozone on Unsaturated Tear Film Wax Esters

Proposal for a chemically consistent way to annotate ions arising from the analysis of reference compounds under ESI conditions: A prerequisite to proper mass spectral database constitution in metabolomics

Gas phase reaction between chromones and solvent in an electrospray ionization source

Contact Info

Product

Resources

About