Mass spectra of fatty acid derivatives, of isopropylidenes of novel glyceryl ethers of cod muscle and of phenolic acetates obtained with the finnigan mat ion trap detector

Abstract

The applicability of the Finnigan MAT Ion Trap Detector (ITD) mass spectrometer for structure determination in some selected fatty acids and their derivatives has been investigated. Isopropylidene derivatives of novel glyceryl ethers isolated from cod flesh and of phenolic acetates are included to indicate the potential for diverse structures and to clarify the protonation of ions. The ITD is a simple and unsophisticated gas liquid chromatograph-mass spectrometer, but the spectra obtained are in most respects comparable to those from more conventional electron impact mass spectrometers. However, due to the comparatively high background pressure (approximately 10(-3) torr) in the ionization chamber of the ITD, there is a tendency for both neutral and ionized molecules to acquire protons from other molecules or fragments through collision. In many cases, the molecular ion was observed as the protonated molecular ion (M + 1), as in chemical ionization mass spectrometry. These interactions can be minimized if the sample load is decreased. Phenolic acetates exhibit not only protonation of the molecular ion, but also protonation of stable fragmented neutral molecules or ions.

Conjugated linoleic acid concentration in processed cheese

“…Peroxide values were determined on extracted fat by thiosulfate titration {13). CLA peaks were identified by comparison with retention times of the CLA reference standard and were further confirmed by mass spectral analysis on a gas chromatography/mass spectrometry (GC/MS) ion trap detector (ITD) system (16). Fatty acid methyl esters were prepared using boron trifluoride in methanol (15).…”

Fatty Acid Composition of Three Cultured Algal Species (Isochvysis galbana, Chaetoceros gracilis and Chaetoceros calcitrans) Used as Food for Bivalve Larvae

“…Analytical GLC of the FAME was camed out in a Perkin-Elmer Model 9 10 equipped with a flame ionization detector (FID) and a flexible fused silica capillary column (30 m in length x 0.25 mm internal diameter) with bonded Carbowax-20M as the liquid phase (SUPELCOWAX-10, Supelco Inc., Bellefonte, Pennsylvania). This liquid phase (polyglycol Carbowax-20M in "bonded" form in capillary columns) has been proposed as especially suitable for natural marine lipid systems, and retention data have been published (Ackman 1984(Ackman , 1986(Ackman , 1987Christie 1988). It is being tested in proposed standard methods for the GLC of fatty acids of marine origin (Firestone 1986).…”

“…The mass spectrum of the peak in question was not specific for bond position but was similar to those obtained for other PUFA and showed the protonated molecular ion appearing at mass/ charge (m/z) 3 19 (monoisotopic molecular weight of 20:4w6 methyl ester is 318). In ITD GUMS of FAME the molecular ion usually appears in the protonated (MH+) form (Ratnayake et al 1986). The advantages of high resolution GLC for identifications through retention time are such that other 20:4 structures are precluded and the confirmation of mass is satisfactory proof of AA (Ackman 1987).…”

Ether‐Type Moieties in the Lipid Part of Glycoinositolphospholipids of Acanthamoeba rhysodes

“…The individual spots were scraped and directly analyzed by GC–MS. The base peak in the spectra of the isopropylidene derivatives of lyso -glyceryl ethers at 101  m / z [31] (Fig. 2b) and the presence of ions [M-15] + at EI mode of fragmentation were identified only for the compounds from the spot with R F 0.42.…”