Project Details:

Guidelines for modulated-temperature differential scanning calorimetry (MTDSC)

Project No.:2007-002-1-100
Start date:2007-01-01
End date:
Division:Physical and Biophysical Chemistry Division
Objective:
Recommendations on methods of operation and guidelines on standardized ways of selecting the different parameters of modulation in the use of modulated-temperature differential scanning calorimeters; including the multi frequency temperature pulses technique.
Description:
Modulated-temperature differential scanning thermal analysis techniques are widely used in many fields. Particularly in pharmaceutical, food and polymer studies where first order transitions, glass transitions and polymorphism are key issues. All sorts of relaxation phenomena as well as coupled thermal and kinetic contributions can advantageously be investigated and selectively studied with such techniques. Produced commercially by a number of companies, sophisticated instruments are used by individuals without the required level of knowledge and expertise necessary to extract the correct information from well established procedures. Typically, calorimetric measurements are subject to systematic errors especially when they depend upon the choice of physical parameters such as amplitude and period of modulation and the temperature scanning rate. Not only the instrument used plays an important role but the sample itself to investigate requires the parameters to be tuned to optimize the response of the instrument in order to eliminate systematic errors and get full unambiguous information. It has to be recognized that whatever the instrument used the same information must be obtained on a given sample.

All thermal analysis techniques where a modulation is superimposed to the temperature ramp will be reviewed underlying in each case the basic principles and the derived mathematical description of the data treatment. The different possible thermal modes (quasi-isothermal, heat only…) will be considered and the estimation of the corresponding run parameters established. The different methods of measurement and calculation of the main thermodynamic quantities, such as specific heat capacities, first order transitions and glass transitions, will be carefully analyzed. Particular attention will be paid to the separation of kinetic effects with emphasis on reversing and non-reversing aspects of the observed phenomena.

On the different points listed above clear description should be made of the operating procedures and methodologies. The project should bring a consistent set of recommendations to be internationally approved for the use of modulated-temperature calorimetry.
Progress:
<project announcement published in Chem. Int. Jul/Aug 2007, p. 20>