Methods[edit]
The TGA instrument continuously weighs a sample as it is heated to temperatures of up to 2000 °C for coupling with FTIR and Mass spectrometry gas analysis. As the temperature increases, various components of the sample are decomposed and the weight percentage of each resulting mass change can be measured. Results are plotted with temperature on the X-axis and mass loss on the Y-axis. The data can be adjusted using curve smoothing and first derivatives are often also plotted to determine points of inflection for more in-depth interpretations (see discussion on Trace Analysis). TGA instruments can be temperature calibrated with melting point standards or Curie point of ferromagnetic materials such as Fe or Ni. A ferromagnetic material is placed in the sample pan which is placed in a magnetic field. The standard is heated and at the Curie point the material becomes paramagnetic which nullifies the apparent weight change effect of the magnetic field.