manufacturers may look quite differently, but work or
operate similarly. Here we use a DSC Q2000
(TA Instruments, Inc., New Castle, DE) as an example.
(b) Open the Q Series Explorer program in the computer.
Select the “SUMMARY PAGE,” enter the following
information: test mode, sample name, net sample mass
(W 1 À W 0 ), crucible mass (W 0 ), and the data file name as
well as the location where the electronic data file is to be
saved.
(c) Select the “PROCEDURE PAGE” and create a test
method. Click on “EDITOR” to open the method dialog
box. In the method dialog box, choose a segment function to enter method inputs for the 10% maltodextrin
solution and the incubated tendon tissue as follows:
Ramp at 5
C/min from the room temperature to 0
C;
ramp at 0.5
C per min to À80
C; isothermal for 10 min;
and ramp at 2
C per min to 20
C (see Note 5). Click the
“APPLY” button at the bottom of the page to save the
method.
(d) Any other information may be entered at the “NOTES
PAGE.”
6. Start the DSC measurement. Upon completion, unload the
test sample from the DSC cell. Repeat for steps 5 and 6 for
the next measurement.
3.3 Data Analysis
The data file of a DSC measurement can be retrieved for analysis
with the instrument-specific software. Data can be plotted with
different thermal signals (heat flow, heat capacity, etc.) against
temperature or time. Figure 3 shows the plot of heat flow against
warming temperature for a 10% maltodextrin solution (prepared in
phosphate-buffered saline, pH 7.4). There is a glass transition of
the freeze-concentrated amorphous solution visible around À20
C
and an ice-melting event starting at À12
C. Expand the warming
segment of the DSC thermogram between À35 and À10
C, using
the software’s graph-plotting tools. Use the “GLASS TRANSITION” on the “ANALYZE” menu to calculate the onset-, mid-,
and end-point temperatures of glass transition. Set the lower limit
at a point about À25
C (before the transition) and the upper limit
at a point about À15
C (after the transition). “ACCEPT” these
limits to calculate the glass transition temperature. The onset T
0
g is
À21.3
C as displayed in the inset. Then, use the “INTEGRATION” on the “ANALYZE” menu to calculate the onset
ice-melting temperature and the melting enthalpy.
DSC Analysis of Thermophysical Properties
291
operate similarly. Here we use a DSC Q2000
(TA Instruments, Inc., New Castle, DE) as an example.
(b) Open the Q Series Explorer program in the computer.
Select the “SUMMARY PAGE,” enter the following
information: test mode, sample name, net sample mass
(W 1 À W 0 ), crucible mass (W 0 ), and the data file name as
well as the location where the electronic data file is to be
saved.
(c) Select the “PROCEDURE PAGE” and create a test
method. Click on “EDITOR” to open the method dialog
box. In the method dialog box, choose a segment function to enter method inputs for the 10% maltodextrin
solution and the incubated tendon tissue as follows:
Ramp at 5
C/min from the room temperature to 0
C;
ramp at 0.5
C per min to À80
C; isothermal for 10 min;
and ramp at 2
C per min to 20
C (see Note 5). Click the
“APPLY” button at the bottom of the page to save the
method.
(d) Any other information may be entered at the “NOTES
PAGE.”
6. Start the DSC measurement. Upon completion, unload the
test sample from the DSC cell. Repeat for steps 5 and 6 for
the next measurement.
3.3 Data Analysis
The data file of a DSC measurement can be retrieved for analysis
with the instrument-specific software. Data can be plotted with
different thermal signals (heat flow, heat capacity, etc.) against
temperature or time. Figure 3 shows the plot of heat flow against
warming temperature for a 10% maltodextrin solution (prepared in
phosphate-buffered saline, pH 7.4). There is a glass transition of
the freeze-concentrated amorphous solution visible around À20
C
and an ice-melting event starting at À12
C. Expand the warming
segment of the DSC thermogram between À35 and À10
C, using
the software’s graph-plotting tools. Use the “GLASS TRANSITION” on the “ANALYZE” menu to calculate the onset-, mid-,
and end-point temperatures of glass transition. Set the lower limit
at a point about À25
C (before the transition) and the upper limit
at a point about À15
C (after the transition). “ACCEPT” these
limits to calculate the glass transition temperature. The onset T
0
g is
À21.3
C as displayed in the inset. Then, use the “INTEGRATION” on the “ANALYZE” menu to calculate the onset
ice-melting temperature and the melting enthalpy.
DSC Analysis of Thermophysical Properties
291