Once all four peaks ( Glycerin, Mono, Di and
Tri ) have been calibrated at Level 1, Load the
previously run and saved Level 2 chroma-
togram. Go through the same procedure ex-
cept at Level 2. Note that theRe-calibration
window requires you to select Level 2.
At theCalibrationwindow, enter the Level 2
amount ( 2500 forMonoOlein ), then hit the
Accept New button. Again the ratio of the
MonoOlein peak area divided by the area of
theTricaprin internal standard peak is calcu-
lated and entered into the cell just to the right
of the Level 2 amount.
Do the same procedure for Glycerin, DiOlein
andTriOlein.
Then Load the Level 3 chromatogram and re-
peat the calibration process for Level 3 for
each of the 4 peaks.
Repeat for Level 4 and Level 5.
After calibrating all five levels, the calibration
curve for each peak should look like the
MonoOlein example shown at right. Note that
the points on the curve should form a straight
line.
Some analysts ( who do not have to follow the
ASTMMethod 6584 exactly ) elect to save
time and just calibrate at Level 5 ( instead of
the 5 levels ). Since the curve is linear any-
way, a single point calibration at Level 5will
produce the same curve as plotting the 5 lev-
els and takemuch less time.
PerformingASTM6584 freeand total glycerin in
BioDiesel usinganSRI GasChromatograph
andPeakSimple software version3.67
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