Thermal gravimetric analysis (TGA) is a technique that measures the sample mass as a function of temperature. Imagine that you put a sample on a balance and track its weight as it is heated in an oven. By tracking the sample mass you can observe if there is any weight loss or weight gain during heating. And the weight loss or weight gain you observe from a TGA test can usually be correlated to some aspect of the sample.
TGA analysis is useful in measuring residual solvent content and percent solids. In some instances, TGA analysis is adapted for quality assurance, which replaces other analytical methods such as drying samples in an oven and quantitative GC analysis of solvents.
There are many products made in solutions. While in solution, the solids content is controlled so that the manufacturing process can be executed as desired. TGA analysis has been used here to measure the percent solids content of the solution. At the end of manufacturing process, solvents are removed from the finishing products. The residual solvent content in a product can also be verified by TGA analysis.
TGA analysis is also useful in applications where very low volatile content is expected of a material. For example, in semiconductor industry and in solar panel industry where outgassing may interfere with product performance, material selection is chosen so that minimal weight loss occurs during product life. In this case, TGA analysis has been used to screen samples for material selection during product development and it is adapted for quality control during material manufacturing.