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Ammonia Concentration in the Eluent Influences Fragmentation Pattern of Triacylglycerols in Mass Spectrometry Analysis
Correct assessment of the fatty acyl at the glycerol -2 position in triacylglycerol (TAG) analysis by liquid chromatography and mass spectrometry (LC-MS) is challenging. Ammonium hydroxide (NH OH) is the preferred choice for the solvent additive for the formation of the ammonium adduct ([M + NH ] )....
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Published in: | Metabolites 2022-05, Vol.12 (5), p.452 |
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Main Authors: | , , |
Format: | Article |
Language: | English |
Subjects: | |
Citations: | Items that this one cites |
Online Access: | Get full text |
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Summary: | Correct assessment of the fatty acyl at the glycerol
-2 position in triacylglycerol (TAG) analysis by liquid chromatography and mass spectrometry (LC-MS) is challenging. Ammonium hydroxide (NH
OH) is the preferred choice for the solvent additive for the formation of the ammonium adduct ([M + NH
]
). In this study, the influence of different NH
OH concentrations in the eluents on TAG adduct formation and fragmentation under LC-MS analysis was assessed. Increasing NH
OH concentrations delayed the chromatographic elution time according to a power function. The [M + NH
]
and [M + ACN + NH
]
adducts (where ACN means acetonitrile) were formed at all ammonium concentrations assayed. [M + ACN + NH
]
predominated above 18.26 mM [NH
OH], and the intensity of [M + NH
]
dropped. TAG fragmentation for fatty acyl release in the MS
was reduced with increasing [M + ACN + NH
]
adduct, which suggests that ACN stabilizes the adduct in a way that inhibits the rupture of the ester bonds in TAGs. A linear equation (H
= a × H
, where
-I refers to the
position of the glycerol (I = 1, 2, or 3) and H is the peak height) was deduced to quantify the dehydroxydiacylglycerol fragment intensity in relation to [M + NH
]
intensity in the full scan. This equation had a slope mean value of 0.369 ± 0.058 for the
-1 and
-3 positions, and of 0.188 ± 0.007 for the
-2 position. |
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ISSN: | 2218-1989 2218-1989 |
DOI: | 10.3390/metabo12050452 |