Connect carrier gas, hydrogen and air to the
GC. Helium is recommended as carrier gas,
while the hydrogen and air are required for the
FID ( flame ionization detector ) which is used
to detect the samplemolecules.
Prepare your calibration standards. The stock
standards ( diluted inPyridine ) canbe purchased
fromRestek ( 800-356-1688 )
.
They are also available fromSupelco and other
lab suppliers.
Unfortunatelywe have not found any one source
for all the items.
Youwill need:
glycerin ( 500ppm ) Restek# 33020
butanetriol ( 1000ppm ) Restek# 33024
monoolien ( 10000ppm ) Restek# 33021
tricaprin ( 8000ppm ) Restek# 33025
diolien ( 5000ppm ) Restek# 33022
triolien ( 5000ppm ) Restek# 33023
MSTFA ( DerivatizationReagent ) Restek# 35601
Heptane ( a common solvent ) Sigma# 34873-1L
8ml vialsGrace# 98862 or
Cole-Parmer#WU-08919-86
100ul syringeGrace# 85012
DisposablepipetsSigma#Z350613-400EA
TheASTM 6584method specifies that for the
highest calibration level ( level 5 ), 100ul of each
material ( in pyridine ) is added to an8ml vial
alongwith 100ul of MSTFA. Allow 20minutes for
the reaction to occur, then add heptane to bring
the final volume to 8ml.
TheASTM 6584method describesmaking the
calibration standards at 5 different levels, so the
level 1 calibration standard is prepared using 10ul
of each startingmaterial instead of 100ul, but the
procedure is otherwise the same.
PerformingASTM6584 freeand total glycerin in
BioDiesel usinganSRI GasChromatograph
andPeakSimple software version3.67
A100ul syringe is helpful formaking thedilutions
alongwith vials, andpipets.
Youwill need the startingmaterials plusMSTFAand
Heptane. Somepyridine is alsohandy to
haveonhand.
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