Acylglycerols (or glycerides) are formed of mono-, di- and
triacylglycerol classes.
In tissue extracts the bulk of glycerides is in fact mainly formed by triacylglycerols with
traces of the other classes. This is the case for blood or plasma where only
triacylglycerols are found. Thus, in general, the estimation of total glycerides is made
by the estimation of glycerol and this is quoted as "triacylglycerol" content.
If present in sufficient amounts, the estimation of mono- and diglycerides can be made
with the same technique after their separation by TLC or column chromatography.
Determination of glycerol in acylglycerols
A very simple but non-specific method which is also useful for
all lipid classes may be used for a first approximation of the lipid content in
crude or purified extracts or for the estimation of lipid fractions separated by
TLC.
This method is based on charring of lipids in hot concentrated sulfuric acid.
Charring method for determination of lipids
When a precise study of one of the acylglycerol classes is
needed, it becomes evident that each class must be separated from the neutral lipid
fraction previously purified by silicic acid column chromatography. C. If large amounts of
acylglycerols are needed (several grams) , they can be separated preparatively by column
chromatography with silicic acid or Florisil as adsorbents. The elution is done with a
stepwise sequence with hexane containing increasing proportions of diethyl ether. Most
frequently, the separation is readily made by preparative or analytical TLC since only
some mg of each lipid are needed for their complete analysis and quantification.
Thin-layer chromatography of acylglycerols
Each of the
acylglycol
classes can be the subject of various analyses such as fatty acid characterization or
separation into molecular species differing in fatty acid chain length and degree of
unsaturation.
To know more about
Analysis of...
Monoacylglycerols
Diacylglycerols
Triacylglycerols
