Install a capillary column in the oven of the SRI GC.
The ASTMmethod suggests a 12meter .32mm id
narrow-bore column coupledwith a 2.5meter guard
column but permits the use of any columnwhich ex-
hibits acceptable resolution of the glyceride analytes.
For ease of use, SRI prefers a 15meter fused silica
linedmetal capillary column commonly called awide-
boreMXT column. The ideal column has a thin film
( .1-.25microns thick ) and a temperature rating of
380C or higher )
This type of column is
unbreakable
( unlike plain
fused silica columns ) and allows the injection syringe
to deposit the sample directly into the bore of the col-
umn itself. This is important because heated or split/
splitless injectors can discriminate against high boiling
analytes like triglycerides. The ASTM 6584method
specifies cool-on-column injection like that found as
standard equipment on all SRI gas chromatographs
to avoid boiling point discrimination.
PerformingASTM 6584 free and total glycerin in
BioDiesel using anSRI GasChromatograph
andPeakSimple software
Restek fused silica lined stainless steel MXT
5 .53mm id capillary column coiled to 3.5 inches
ChrompackHT5 .32mm id fused silca coupled
with 2.5meter .53mm id guard column. A 1/16’”
stainless steel union with graphite ferrules con-
nects the guard column to the analytical column.
The 26 ga. Syringe needle fits inside the .53mm
column to accomplish a cool on-column injection
as specified in themethod.
