TA Instruments TGA 2950 - Page 154

Appendix B
B–16 TA I NSTRUMENTS TGA 2950
Figure B.6
As can be seen in these examples, calcium
oxalate has three well resolved transitions
corresponding to the loss of water (1st weight
loss), carbon monoxide (2nd weight loss) and
carbon dioxide (3rd weight loss). Comparing
the 20
°
C/minute and the 1
°
C/minute scans
(Figures B.1 and B.2), we see some improve-
ment in resolution of the water loss (1st transi-
tion), but little improvement in the other two
transitions.
Note that the transition temperatures in the
slower scan are shifted to lower temperatures as
expected. The 20
°
C/minute scan took 39 minutes
and the 1
°
C/minute scan took nearly 13 hours to
complete.
(a) 1
°
C/min, Normal Ramp; (b) Res 5.0, 50
°
C/min; (c) Res 4.0, 50
°
C/
min; (d) Res 3.0, 50
°
C/min; (e) 20
°
C/min, Normal Ramp