Ro. Adlof, NORMAL-PHASE SEPARATION EFFECTS WITH LIPIDS ON A SILVER ION HIGH-PERFORMANCE LIQUID-CHROMATOGRAPHY COLUMN, Journal of chromatography, 764(2), 1997, pp. 337-340
Citations number
14
Categorie Soggetti
Chemistry Analytical","Biochemical Research Methods
The separation of saturated fatty acids (as the methyl esters and as t
riacylglycerols) of differing chain lengths by silver ion chromatograp
hy (ChromSpher Lipids; containing silver ions; Chrompack, Middelburg,
Netherlands) was studied. The retention characteristics (isocratic sol
vent system of acetonitrile in hexane) of saturated fatty acid methyl
esters and homogeneous, saturated triacylglycerols were found to be in
versely related to the number of carbon atoms in the fatty acid(s). Th
us methyl stearate eluted first and methyl acetate eluted last; for tr
iacylglycerols, tripalmitoylglycerol eluted first while triacetin was
strongly retained (11 min vs. 70 min). While mixtures of fatty acid me
thyl esters and of triacylglycerols could be separated, resolution was
found to improve at higher concentrations of acetonitrile, a characte
ristic of normal-phase separations. In the absence of carbon-carbon do
uble or triple bonds, the effects of the more polar silanol groups of
the column packing tended to override the silver ion contributions (in
teraction of silver ions with the unpaired electrons of the carbonyl o
xygens), resulting in separations similar to those observed in silica
thin layer and normal-phase high-performance liquid chromatography.