1. Prepare a SRM-2232 sample (5–8 mg) in an aluminum crucible. Record the actual mass with precision to 0.0001 g. Run the
sample with the following four-step temperature ramping program: Ramp at 20
C per min from the room temperature to
180
C; ramp at 20
C per min to 130
C; isothermal for 5 min;
and ramp at 2
C per min to 170
C.
2. Determine the onset temperature (T m ) of fusion (melting) and
heat (enthalpy) of fusion (ΔH) of the indium sample according
to data of the second slow heating segment (rom 130–170
C
at 2
C per min).
3. The certified T m and ΔH values of SRM-2232 indium by NIST
are 156.5985 Æ 0.00034
C and 28.51 Æ 0.19 J/g, respectively. The measured values of T m and ΔH meet the accuracy
requirement if T m is 156.6 Æ 0.3
C and ΔH is 28.5 Æ 0.5 J/g.
3.2 Operation
Procedure
The procedure below outlines the basic operation of measuring the
temperatures of glass transition, and ice-melting for a 10% maltodextrin (M180) solution that is used for freeze-drying protection of
tissue matrix in regenerative medicine. The basic DSC operation is
the same for different types of measurements, except with different
temperature/time ramping programs.
1. Turn on the calorimeter. Check the connection to the cooling
system and the purge gas. Make sure the cooling system is
ready.
2. Check that the purge gas is connected, and set to the desired
flow rate at 50 mL per min (see Note 2).
3. Check the cooling system, and make sure it is ready. If a
refrigerant cooling system (RCS) is applied (see Note 3), be
sure a base purge gas is used.
4. Preparation of samples: Weigh the mass of one pair of crucibles,
record weight (W 0 ), and aliquot approximately 10–15 μL test
solution into the pan of crucibles. Place the cover and seal the
crucibles with the press (see Note 4). Weigh the crucibles
containing the sample again (W 1 ) to obtain the net sample
weight (W 1 À W 0 ). For the decellularized human tendon
tissue, cut a flat and small piece (~20 mg), place it flat into
another pan of crucibles for maximal direct contact. Make
another pair of crucibles as the reference.
5. Load the reference and the freeze-drying solution sample
(or the incubated tendon tissue) into their respective positions
of the DSC cell. Make sure to close the DSC lid.
(a) Preparation of measurement: The calorimetric instrument
and its accessory units are controlled by a computer with
method inputs for specific sample measurements. The
software programs developed by different DSC
290
Wendell Q. Sun
sample with the following four-step temperature ramping program: Ramp at 20
C per min from the room temperature to
180
C; ramp at 20
C per min to 130
C; isothermal for 5 min;
and ramp at 2
C per min to 170
C.
2. Determine the onset temperature (T m ) of fusion (melting) and
heat (enthalpy) of fusion (ΔH) of the indium sample according
to data of the second slow heating segment (rom 130–170
C
at 2
C per min).
3. The certified T m and ΔH values of SRM-2232 indium by NIST
are 156.5985 Æ 0.00034
C and 28.51 Æ 0.19 J/g, respectively. The measured values of T m and ΔH meet the accuracy
requirement if T m is 156.6 Æ 0.3
C and ΔH is 28.5 Æ 0.5 J/g.
3.2 Operation
Procedure
The procedure below outlines the basic operation of measuring the
temperatures of glass transition, and ice-melting for a 10% maltodextrin (M180) solution that is used for freeze-drying protection of
tissue matrix in regenerative medicine. The basic DSC operation is
the same for different types of measurements, except with different
temperature/time ramping programs.
1. Turn on the calorimeter. Check the connection to the cooling
system and the purge gas. Make sure the cooling system is
ready.
2. Check that the purge gas is connected, and set to the desired
flow rate at 50 mL per min (see Note 2).
3. Check the cooling system, and make sure it is ready. If a
refrigerant cooling system (RCS) is applied (see Note 3), be
sure a base purge gas is used.
4. Preparation of samples: Weigh the mass of one pair of crucibles,
record weight (W 0 ), and aliquot approximately 10–15 μL test
solution into the pan of crucibles. Place the cover and seal the
crucibles with the press (see Note 4). Weigh the crucibles
containing the sample again (W 1 ) to obtain the net sample
weight (W 1 À W 0 ). For the decellularized human tendon
tissue, cut a flat and small piece (~20 mg), place it flat into
another pan of crucibles for maximal direct contact. Make
another pair of crucibles as the reference.
5. Load the reference and the freeze-drying solution sample
(or the incubated tendon tissue) into their respective positions
of the DSC cell. Make sure to close the DSC lid.
(a) Preparation of measurement: The calorimetric instrument
and its accessory units are controlled by a computer with
method inputs for specific sample measurements. The
software programs developed by different DSC
290
Wendell Q. Sun