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Fragmentation of methyl abscisate and pentafluorobenzyl abscisate in methane electron capture negative ionization tandem mass spectrometry
Author(s) -
Netting A. G.,
Lidgard R. O.
Publication year - 1999
Publication title -
journal of mass spectrometry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.475
H-Index - 121
eISSN - 1096-9888
pISSN - 1076-5174
DOI - 10.1002/(sici)1096-9888(199906)34:6<611::aid-jms813>3.0.co;2-1
Subject(s) - chemistry , abscisic acid , mass spectrometry , electron ionization , tandem mass spectrometry , chemical ionization , mass spectrum , fragmentation (computing) , ion , chromatography , stereochemistry , ionization , organic chemistry , biochemistry , computer science , gene , operating system
The methyl and pentafluorobenzyl esters of the plant hormone abscisic acid were subjected to methane chemical ionization tandem mass spectrometry (MS/MS). The spectra obtained allow the unambiguous identification of abscisic acid in a few milligrams of plant material. In full‐scan mode pentafluorobenzyl (PFB) abscisate (ABA) gave three significant ions at m/z 263 ([M −PFB] − ), m/z 219 ([M −PFB −CO 2 ] − ) and m/z 153 ([M −PFB −side chain] − ). Each of these was subjected to MS/MS and structures were assigned to the product ions using the labelled analogues, PFB[1′‐ 18 O]ABA, PFB[4′‐ 18 O]ABA, PFB[side‐chain‐ 2 H 4 ]ABA and PFB[ring‐ 2 H 6 ]ABA. Similarly, in full‐scan mode, methyl abscisate gave three significant ions at m/z 278 (M − ), m/z 260 ([M −H 2 O] − ) and m/z 245 ([M −H −CH 3 OH] − ) and in MS/MS the use of the methyl esters of the above labelled analogues, and [ 2 H]methyl abscisate, allowed structures to be assigned to the product ions. Using these results it will be possible to dissect abscisic acid so that most labelled atoms from 13 C‐labelled substrates will be able to be uniquely identified from a few nanograms of 13 C‐labelled abscisic acid. If sufficient incorporation of 13 C‐labelled substrates can be obtained it should be possible to investigate the pathway(s) of abscisic acid biosynthesis using less than 1 g of plant material. Copyright © 1999 John Wiley & Sons, Ltd.