Thermogravimetric Analysis
Definition and meaning of Thermogravimetric Analysis in chemistry.
Thermogravimetric analysis is an analytical technique in which the mass of a sample is measured continuously as it is heated, cooled, or held at a constant temperature in a strictly controlled atmosphere. This highly precise method is primarily used to determine the thermal stability and material composition of substances by monitoring weight changes associated with thermal decomposition, oxidation, or the loss of volatile components.
In more detail
During the analytical procedure, an exceptionally sensitive thermobalance records the sample's weight while an automated furnace precisely dictates the desired temperature program. As the subject material undergoes significant physical or chemical changes, such as solvent vaporization or structural degradation, it consequently loses or gains mass. The resulting experimental data is plotted as a thermogravimetric curve, illustrating the sample's mass percentage on the y-axis against temperature or elapsed time on the x-axis. This graphical profile provides crucial information about a substance's inherent purity, intrinsic moisture content, and the precise temperatures at which various decomposition stages aggressively occur. It is highly valued in materials science for evaluating the thermal endurance of novel polymers and complex inorganic compounds.
Key facts
| Field | Analytical Chemistry |
|---|---|
| Measured variable | Sample mass as a function of temperature or time |
| Common applications | Polymer degradation and precise moisture analysis |
Thermogravimetric analysis can be effectively used to determine the exact water content of a hydrated salt by measuring the distinct mass lost as the solid sample is heated past the boiling point of water.
Frequently asked questions
What kind of atmosphere is typically used in TGA?
It can be performed in an inert atmosphere like nitrogen to study clean decomposition, or in an active atmosphere like oxygen to study rapid oxidation.
Can TGA independently identify specific gases released?
Not by itself, but it is often coupled directly with mass spectrometry or infrared spectroscopy to accurately identify the evolved gases.