BET-analysis – Brunauer, Emmett, Teller

The BET method is used to determine the specific surface area of solids and is especially applicable for the analysis of porous and disperse solids. During the analysis, the absorbed amount of an introduced gas (usually nitrogen) is determined under nitrogen cooling. Because of a subsequent pressure reduction, an amount of the gas desorbs from the sample surface, allowing to determine the adsorption-desorption isotherm. The method allows a calculation of the average pore size, the pore volume as well as the pore size distribution.

By determining the surface characteristics, conclusions can be made about the performance and quality of a broad range of materials. The analysis is used for example to analyze fillers, catalysts, ceramics, metal powders, pharmaceuticals or pigments.