PMID- 17526066
OWN - NLM
STAT- MEDLINE
DCOM- 20070802
LR  - 20131121
IS  - 0951-4198 (Print)
IS  - 0951-4198 (Linking)
VI  - 21
IP  - 13
DP  - 2007
TI  - Reducing fragmentation observed in the matrix-assisted laser 
      desorption/ionization time-of-flight mass spectrometric analysis of 
      triacylglycerols in vegetable oils.
PG  - 1951-7
AB  - Edible oils consist primarily of triacylglycerols (TAGs). Matrix-assisted laser 
      desorption/ionization time-of-flight (MALDI-TOF) mass spectra of the oils are 
      typically dominated by sodium adducts of these TAGs but also show prominent 
      fragment ions (that do not contain sodium), which can interfere with analytical 
      measurements of other components in oils. The fragments seemingly correspond to 
      the loss of a fatty acid moiety from the sodiated TAGs as a sodium salt: RCOONa. 
      However, a previous study suggested that the fragments actually arise from nearly 
      complete fragmentation of unseen protonated TAGs. These authors suggested that 
      the fragmentation occurs so rapidly and completely that protonated TAGs are not 
      normally observed in the spectra of these oils. In this paper, we present 
      evidence to support their theory and also demonstrate an approach to eliminate 
      these interfering ions from the MALDI-TOF mass spectra via addition of a base to 
      the matrix/sample mixture. The added base does not impede formation of the 
      sodiated TAGs, but does significantly reduce the amount of fragments observed. We 
      propose that this occurs by depleting the H+ ions from the matrix, thus 
      preventing the formation of significant numbers of protonated TAGs in the first 
      place. For measurements by MALDI-TOF, the relative abundances of the fragment 
      ions are related to the strength of the base, and can be almost completely 
      eliminated. However, in longer time-scale experiments such as in post-source 
      decay and Fourier transform mass spectrometry, sodiated and non-sodiated 
      diacylglycerol (DAG)-like fragments are present in spectra, regardless of whether 
      or not a base is added to the sample.
CI  - Copyright (c) 2007 John Wiley & Sons, Ltd.
FAU - Gidden, Jennifer
AU  - Gidden J
AD  - Arkansas Statewide Mass Spectrometry Facility, University of Arkansas, 
      Fayetteville, AR 72701, USA.
FAU - Liyanage, Rohana
AU  - Liyanage R
FAU - Durham, Bill
AU  - Durham B
FAU - Lay, Jackson O Jr
AU  - Lay JO Jr
LA  - eng
PT  - Journal Article
PL  - England
TA  - Rapid Commun Mass Spectrom
JT  - Rapid communications in mass spectrometry : RCM
JID - 8802365
RN  - 0 (Carbonates)
RN  - 0 (Gentisates)
RN  - 0 (Hexanes)
RN  - 0 (Plant Oils)
RN  - 0 (Protons)
RN  - 0 (Solvents)
RN  - 0 (Triglycerides)
RN  - 059QF0KO0R (Water)
RN  - 55X04QC32I (Sodium Hydroxide)
RN  - 7664-41-7 (Ammonia)
RN  - NJ5VT0FKLJ (ammonium carbonate)
RN  - VP36V95O3T (2,5-dihydroxybenzoic acid)
RN  - Y4S76JWI15 (Methanol)
SB  - IM
MH  - Ammonia/pharmacology
MH  - Carbonates/pharmacology
MH  - Gentisates/chemistry
MH  - Hexanes/chemistry
MH  - Methanol/chemistry
MH  - Molecular Weight
MH  - Plant Oils/*chemistry
MH  - Protons
MH  - Sodium Hydroxide/pharmacology
MH  - Solvents/chemistry
MH  - *Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
MH  - Triglycerides/*analysis
MH  - Water/chemistry
EDAT- 2007/05/26 09:00
MHDA- 2007/08/03 09:00
CRDT- 2007/05/26 09:00
PHST- 2007/05/26 09:00 [pubmed]
PHST- 2007/08/03 09:00 [medline]
PHST- 2007/05/26 09:00 [entrez]
AID - 10.1002/rcm.3041 [doi]
PST - ppublish
SO  - Rapid Commun Mass Spectrom. 2007;21(13):1951-7. doi: 10.1002/rcm.3041.