4. Thermal analysis.pptx Pharmaceutical Analysis

Pharmaceutical Analysis Pharm D

1. Thermal Analysis Abrar Ahmad

2. Introduction to Thermal Analysis Thermal analysis is a branch of materials science focused on how materials behave when temperatures change . Techniques in Thermal Analysis 1. Differential Scanning Calorimetry (DSC ) Differential Scanning Calorimetry (DSC) is like a thermometer for materials. It measures how much heat flows into or out of a substance as we change its temperature. By comparing it to a reference, we can see when the material melts, freezes, or undergoes chemical changes.

3. 2. Differential Thermal Analysis Compares the temperature of a sample to that of an inert reference material as they both undergo controlled temperature changes. P articularly useful for detecting phase transitions, Melting or crystallization , Chemical reactions Decomposition processes

4. 3. Thermogravimetric Analysis (TGA) Technique used to measure the change in mass of a sample as it is heated or cooled over time. V aluable for studying decomposition processes, volatile components, and chemical reactions in materials. TGA can provide insights into the thermal stability, decomposition kinetics, and composition of substances.

5. Differential Scanning Calorimetry (DSC)

6. Introduction to DSC T hermoanalytical technique used to measure the difference in heat flow between sample and a reference material W as developed by E. S. Watson and M. J. O'Neill in 1962 , and introduced commercially at the 1963 This difference in heat flow is recorded as a function of temperature. By comparing the heat flow of the sample to that of the reference material, DSC provides valuable insights into the thermal behavior of sample, e.g. phase transitions, chemical reactions, and thermal stability.

7. Principle of DSC DSC operates on the principle that when a sample undergoes a physical or chemical change, it absorbs or releases heat . This heat flow is measured differentially between the sample and a reference material as both are subjected to identical thermal conditions . Any temperature difference between the sample and reference is recorded as a function of temperature.

8. Instrumentation Sample and Reference Cells These are two separate compartments where the sample and reference material are placed. D esigned to ensure uniform heating and cooling. Sample cell contains the substance being analyzed R eference cell typically contains an inert material with known thermal properties, like an empty pan or an inert material such as alumina .

9. 2. Thermal Sensors

10. 3. Furnace The furnace provides controlled heating or cooling to both the sample and reference cells. It allows for precise temperature control and can ramp up or down at predetermined rates to induce thermal changes in sample.

11. 4. Data Acquisition System This system records the temperature difference (∆T) between the sample and reference cells as a function of temperature . It typically consists of software that controls the experiment parameters and collects and analyzes the data obtained during the DSC experiment

12. Loaded into the sample cell of the DSC instrument. An identical procedure is followed for reference material, which is typically an inert substance with known thermal properties. Both cells are sealed to prevent any loss or gain of material during the experiment .

13. Applications

14. Applications