Thermogravimetric analysis is a method in which a substance's mass is often tracked as a function of temperature or time while the sample specimen is typically put to a controlled temperature programme in a controlled atmosphere. Alternative Definition: TGA is a method that measures changes in material weight as a result of heating.
A Simple TGA Concept to remember: TGA measures a sample’s weight as it is normally heated or cooled in a furnace. A TGA comprises of a sample pan supported by a precision balance. That pan resides in a furnace and is normally heated or cooled during the experiment.
Typically, the experiment involves monitoring the sample's mass. The sample environment is managed using a purge gas. This gas, which passes over the sample and leaves through an exhaust, may be inert or reactive.
Types of TGA
PerkinElmer offers types of TGAs,
- a top-loading TGA 4000™
- a bottom-loading or hang-down, TGA 8000™.
The TGA 4000 uses a "stem" support rod to hold the sample pan above the balance. Using a "hang down" below the balance, the TGA 8000 supports the sample pan. Both methods use gravity to provide incredibly precise, repeatable measurement.
Both TGAs can be used for Evolved Gas Analysis included in the hyphenated analytical system
- TGA 8000 – IR, MS, or GC/MS
- TGA 4000 – IR or MS
How TGA Method Works
TGA analysis explains how a material's mass changes over time and at different temperatures. In this method the sample is usually heated from ambient to 1000 degrees in nitrogen or air, then the resultant weight reduction is always calculated which happens because of ash content material, polymer breakdown, carbon black, moisture, and semi-volatile chemicals.
The lack of surface adsorbed solvent may be outstanding from solvent in the crystal lattice and degradation losses. The measurements are usually completed in atmospheres having controlled humidity and oxygen concentration to reveal interactions with the drug substance, among drug materials, and active substances and excipients or packaging materials.
What can we get from TGA?
- It is useful in routine analysis of content material determination to get a correct understanding of sample composition.
- TGA analyzes the changes in size, shape, and usual mass while exposed to various temperatures.
- The mass change of the materials being tested is accurately described.
- It gives the information required for a variety of material characterization goals.
- Helps in determining the water/carbon content or other residual solvents in the material.
- allows for the examination of reactions with reactive glasses, such as oxygen or air.
Method
TGA analysis is always performed by progressively elevating the temperature of a sample in a furnace as weight is usually measured on an analytical balance that remains outside the furnace.
Thermogravimetric analysis instrument measures the modifications in a sample’s weight at a specific temperature by enclosing the piece in an oven. In Thermogravimetric analysis, the result acquired appears as a continuous chart record, a schematic, typical, single-step decomposition reaction.
We also test for moisture and ash. This procedure involves continuously checking for changes in the sample's mass. As a result, we have a thorough understanding of how the mass of a particular substance evolves. ISO 11358 standards are used for TGA. Both solids and liquids may use it.
When do I need to adjust my TGA?
The following are reasons for correction:
• Each time you alter the temperature range you've been operating in.
• Whenever the purge gas rate is altered.
• When the purge gas is normally changed.
• When you replace the hang-down wire on the TGA 8000.
Conclusion
In the above blog, we usually recognize the meaning of TGA, its types, how it works, what we get from tga, and its method. A lot of materials are characterized and verified using TGA analysis. TGA applies to most industries. The mainstays of thermogravimetric and evolved gas analysis include environmental, food science, medicinal, and petrochemical applications.
Frequently Asked Questions on Full form of TGA
. What are the constraints of TGA?
The primary problem of TGA methods, specifically that mass lack of volatiles is not equivalent to the formation of degradants, considerably impedes its ability to provide consistent popular indicators of the real extent of degradation
. What are the factors affecting TGA?
Instrumental factors: It relies upon the furnace environment, gas flow rate, heating rate, geometry, and material of the pan. Normally the heating rate of 3.5 °C per minute is usually considered appropriate for the reliability and reproducibility of TGA.
. How much sample is normally required for TGA?
The majority of TGA measurements arise with samples weighing between 1 and 30 mg, usually about 10 mg, though this mass is not mandatory. TGA is a technique to evaluate the loss of mass of the separate constituents of a mixture so that the mass of the minor constituent which is always measured is the most important.