Elution factors of synthetic oxotriacylglycerols as an aid in identification of peroxidized natural triacylglycerols by reverse‐phase high‐performance liquid chromatography with electrospray mass spectrometry

Sjövall, Olli; Kuksis, A.; Marai, L.; Myher, J. J.

doi:10.1007/s11745-997-0155-4

Cited by 51 publications

(68 citation statements)

References 26 publications

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“…This would indicate that the sn-2 isomer eluted before the sn-1,3 isomers. This is in complete agreement with the discussion by Sjovall et al (20), in which they reported that the 2-isomer eluted ahead of the 1,3-isomers for aldehydes and hydroperoxy species, although the elution factors tabulated and pictured for the 2-isomers (20) were longer than the elution factors for the corresponding 1,3-isomers.…”

Section: Resultssupporting

confidence: 92%

“…These two classes could not be distinguished by mass. One approach to identification of core aldehydes has been demonstrated by Sjovall and co-workers (20,21). It will be possible to perform the separation on the unreacted oxidation products mixture and on the reacted product mixture to identify which peaks disappear from the chromatogram of the unreacted mixture and appear at different retention times in the reacted mixture.…”

Section: Resultsmentioning

confidence: 99%

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Electrospray ionization MS of high M.W. TAG oligomers

Byrdwell

Neff

2004

J Americ Oil Chem Soc

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Reported are the on-line LC/electrospray ionization MS of large, high M.W. oligomers formed from heated triolein, a TAG used as a model for dietary oils. Triolein, the major component of olive oil, canola oil, and other dietary oils, was heated at frying temperature, and the TAG oxidation products were separated using RP-HPLC coupled to an ion trap mass spectrometer via an electrospray ionization interface. Ammonium formate was added as a sheath liquid to promote ammonium adduct formation. Masses corresponding to ammonium adducts of intact carbon-linked dimers (m/z 1783-1787), trimers (m/z 2666-2672), and tetramers (m/z 3547-3557) of triolein, with and without additional sites of unsaturation, were observed. Also, dimers, trimers, and tetramers containing one, two, or three additional oxygens, also with and without additional sites of unsaturation, are reported. Based on the formation of some types of triolein dimers, we believe that tristearin might also form dimers, even though it has no readily oxidizable sites of unsaturation. Oxidized tristearin monomers, tristearin dimers, chainaddition products, and chain-shortened products are observed.Paper no. J10594 in JAOCS 81, 13-26 (January 2004).The reactions of atmospheric oxygen with fatty acyl chains to form lipid oxidation products have been studied extensively. Many reviews, book chapters, and books dedicated to lipid oxidation products have been published. One excellent reference describing the various aspects of lipid oxidation at ambient temperature was edited by Chan (1). Frankel has published extensively in the area of lipid oxidation, including thorough review articles (2,3). Studies on the oxidation of model FAME such as methyl oleate and methyl linoleate have long shown that oxidation of lipids initially produces hydroperoxides as the primary oxidation products, and these react further to produce a wide array of secondary products. Early work on the mechanisms and products of oxidation was performed on FA and their methyl esters because these were amenable to GC and GC/MS. Analysis of the FAME of oxidation products was also conducted using direct-exposure probe MS, NMR spectrometry, and others (such as IR spectrometry). At least three broad categories of lipid oxidation products are produced by oxidation of FAME: (i) small volatile oxidation products, (ii) FA fragments, and (iii) dimers, trimers, and other oligomers. The small volatile molecules produced by the breakdown of hydroperoxides have been thoroughly discussed by Frankel (2), Grosch (4), and others. The small volatile oxidation products include alkanes, alkenes, alcohols, aldehydes, ketones, acids, and others. When a small volatile fragment breaks off from the fatty chain, a FA fragment is left behind as a "core aldehyde" or similar residue. The third type of oxidation product, oligomers, are formed when two fatty chains become linked at a site of oxidation. Several classes of dimers of methyl linoleate hydroperoxides were discussed by Miyashita and co-workers (5-7). These were identified by g...

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Section: Resultssupporting

confidence: 92%

Section: Resultsmentioning

confidence: 99%

Electrospray ionization MS of high M.W. TAG oligomers

Byrdwell

Neff

2004

J Americ Oil Chem Soc

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“…Much of our present understanding of the role of TAGs comes from measurement of either the total quantity of TAG present in cells, or fatty acids that can be released from TAGs after isolation and saponification rather than knowledge of changes in unique TAG molecular species. In recent years there has been renewed interest in the development of mass spectrometric methods using electrospray ionization and atmospheric pressure chemical ionization to analyze TAGs at the molecular species level [16][17][18][19]. We recently reported a strategy using MS 3 to analyze TAGs from a complex mixture as the NH 4 + adduct ions generated by electrospray ionization [20].…”

Section: Introductionmentioning

confidence: 99%

Detection of the abundance of diacylglycerol and triacylglycerol molecular species in cells using neutral loss mass spectrometry

Murphy

James

McAnoy

et al. 2007

Analytical Biochemistry

142

122

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Triacylglycerols are neutral lipids present in all mammalian cells as energy reserves and diacylglycerols as intermediates in phospholipid biosynthesis and as signaling molecules. The molecular species of triacylglycerols and diacylglycerols present in mammalian cells are quite complex and previous investigations revealed multiple isobaric species having molecular weights at virtually every even mass between 600-900 daltons, making it difficult to assess changes of individual molecular species after cell activation. A method has been developed using tandem mass spectrometry and neutral loss scanning to quantitatively analyze changes in those glyceryl ester molecular species containing identical fatty acyl groups. This was carried out by neutral loss scanning of 18 common fatty acyl groups where the neutral loss corresponded to the free carboxylic acid plus NH 3 . Deuterium labeled internal standards were used to normalize the signal for each nominal [M +NH 4 ] + ion undergoing this neutral loss reaction. This method was applied in studies of triacylglycerols in RAW 264.7 cells treated with the toll-like receptor 4 ligand Kdo 2 -lipid A. A 50:1-TAG containing 18:1 was found to increase significantly over a 24 hr time course after Kdo 2 -lipid A exposure whereas an isobaric 50:1-TAG containing 16:1 did not change relative to controls.

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“…However, the volatility of some TAGs, especially those containing polyunsaturated fatty acyl groups, require very high temperatures (Ͼ300°C) to elute from a gas chromatograph, which can lead to decomposition in the well known ester pyrolysis reaction. More recently, electrospray ionization and atmospheric pressure ion-ization have been employed to analyze TAGs at the molecular species level using considerably gentler conditions° [12][13][14][15].°Notable°advances°were°made°by°Han and°Gross° [16]°and°Hsu°and°Turk° [17]°using°lithium adducts of TAGs with collisional activation of the [M ϩ Li] ϩ ions to yield diacyl product ions that revealed specific information about acyl groups esterified to individual TAG molecular species. Also, Byrdwell and Neff employed MS 3 to study the composition of synthetic°TAG°species° [18].°Cheng,°Gross,°and°Pittenauer used high-energy collisions of ammonium and sodium adducts of TAGs to elucidate acyl position on the glycerol backbone and double-bond location of unsaturated°acyl°moieties° [19]°of°pure°TAG°molecular°spe-cies.…”

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confidence: 99%

Direct qualitative analysis of triacylglycerols by electrospray mass spectrometry using a linear ion trap

McAnoy

Murphy

2005

J. Am. Soc. Mass Spectrom.

162

149

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Triacylglycerols (TAGs) isolated from a biological sample provide a challenge for mass spectrometric analysis because of the complexity of naturally occurring TAGs, which may contain different fatty acyl substituents resulting in a large number of molecular species having the identical elemental composition. We have investigated the use of mass spectrometry to obtain unambiguous information as to the individual TAG molecular species present in a complex mixture of triacylglycerols using a linear ion trap mass spectrometer. Ammonium adducts of TAGs, [M ϩ NH 4 ] ϩ , were generated by electrospray ionization, which permitted the molecular weight of each TAG molecular species to be determined. The mechanisms involved in the decomposition of the [M ϩ NH 4 ] ϩ and subsequent fragment ions were investigated using deuterium labeling, MS/MS, and MS 3 experiments. Collision induced decomposition of [M ϩ NH 4 ] ϩ ions resulted in the neutral loss of NH 3 and an acyl side-chain (as a carboxylic acid) to generate a diacyl product ion. MS/MS data were used to identify each acyl group present for a given [M ϩ NH 4 ] ϩ ion, and this information could be combined with molecular weight data to identify possible TAG molecular species present in a biological extract. Subsequent MS 3 experiments on the resultant diacyl product ions, which gave rise to acylium (RCO ϩ ) and related ions, enabled unambiguous TAG molecular assignments. These strategies of MS, MS/MS, and MS 3 experiments were applied to identify components within a complex mixture of neutral lipids extracted from RAW 264.7 cells. (J Am Soc Mass Spectrom 2005, 16, 1498 -1509

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Elution factors of synthetic oxotriacylglycerols as an aid in identification of peroxidized natural triacylglycerols by reverse‐phase high‐performance liquid chromatography with electrospray mass spectrometry

Cited by 51 publications

References 26 publications

Electrospray ionization MS of high M.W. TAG oligomers

Electrospray ionization MS of high M.W. TAG oligomers

Detection of the abundance of diacylglycerol and triacylglycerol molecular species in cells using neutral loss mass spectrometry

Direct qualitative analysis of triacylglycerols by electrospray mass spectrometry using a linear ion trap

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