Calibrate the TGA 8000 . 51
Make sure that the curve is displayed with the following axes:
X = Temperature (change by selecting Rescale X from the Display menu and
then select Temperature in the dialog box).
Y = Weight (change by selecting Weight from the Curves menu).
2.
In the Curves menu select the Weight curve.
3.
In the Step Select dialog select step 2 and step 5 through 12. (These two curves
contain data for heating the Curie samples at 20 and 5 degrees per minute. (You can
delete the original weight data curve.
4.
For the active curve, select from the Math menu, derivative, this will display the
derivative curve for the segment you are analyzing.
5.
With the derivative curve active, Select Peak Area from the Calc menu.
Calulate the peak temperature at corresponds to each of the weight loses. This point
will be used to determine one of the points for each weight loss step.
6.
Select Weight Loss curve so the derivative curve goes to the background.
7.
Select Onset from the Calc menu.
8.
Move the two red X marks on the curve. Position the left limit X at the inflection
point of the first derivative curve and place the right limit X past the inflection point
on the level part of the curve. Alternatively type in the values using the peak value
from the derivative calculation as the steepest slope and a temperature on the
trailing baseline.
9.
Click the Calculate button in the Onset dialog box. The Adjust Tangents box
appears.
10.
Adjust the tangents of each point until they cross and each is tangential at the point
selected.
Perform this Onset calculation on each of the eight Curie temperatures (4 at 5 °C/min
and 4 at 20 or 25 °C/min.
11.
Click the Calculate button in the Adjust Tangents dialog box. The onset
temperature is calculated for the sample and displayed on the screen (Onset X).
Summary of Contents for TGA 8000
Page 1: ...TGA 8000 Installation and Hardware Guide THERMAL ANALYSIS...
Page 5: ...5 Safety and Regulatory Information...
Page 19: ...19 Prepare the Laboratory...
Page 25: ...25 Installing the TGA 8000...
Page 55: ...55 TGA 8000 Hardware Maintenance...
Page 68: ...68 TGA 8000 Installation and Hardware Guide...
Page 85: ...85 TGA 8000 Autosampler...