Lipids

, Volume 38, Issue 7, pp 781–791

FA determination in cold water marine samples

Methods

Abstract

The determination of FA in cold water marine samples is challenging because of the presence of large proportions of a variety of labile PUFA. This study was undertaken to establish optimal methods for FA analysis in various sample types present in the marine environment. Several techniques used in FA analysis, including lipid fractionation, FAME formation, and picolinyl ester synthesis, were examined. Neutral lipids, acetone-mobile polar lipids, and phospholipids (PL) were readily separated from each other on columns of activated silica gel, but recoveries of PL were reduced. Deactivation of the silica gel with 20% w/w water produced variable recoveries of PL (66±22%). FAME formation with BF3 gave optimal recoveries, and a method to remove hydrocarbon contamination from these samples before GC analysis using column chromatography was optimized. Picolinyl derivatives of FA are useful in structural determinations with MS, and a new base-catalyzed transesterification method of their synthesis from FAME was developed. Finally, a series of calculations, combining FA proportions with acyl lipid class concentrations, was designed to estimate FA concentrations. In algae and animal samples, these estimates were in good agreement with actual FA concentrations determined by internal standards.

Abbreviations

AMPL

acetone-mobile polar lipid

NL

neutral lipid

NMID

nonmethylene-interrupted dienoic

OSC

Ocean Science Centre

PL

phospholipid

SE/WE

steryl ester/wax ester

TIC

total ion chromatogram

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Copyright information

© AOCS Press 2003

Authors and Affiliations

  1. 1.Ocean Sciences Centre and Chemistry DepartmentMemorial University of NewfoundlandSt. John'sCanada
  2. 2.Biology DepartmentDalhousie UniversityHalifaxCanada

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