BET Surface Area Analysis

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BET Surface area measurement, sometimes termed specific surface area, is undertaken through two fundamentally different techniques, volumetric or flowing gas. In both cases either a single point BET measurement or, more accurately, a multipoint BET measurement is available. Through this, and the application of a choice of adsorbent gases, the surface area of almost any solid sample can be determined.

The different tests available are outlined below. In most cases results are conveyed as pdf files and in addition we offer assistance with interpretation of results at no extra charge

SC6T Test: Multipoint BET Surface Area &  SC7T Test: Single Point BET Surface Area 

The majority of samples are analysed using a Micromeritics TriStar II instrument, a state-of-the-art gas adsorption instrument using the volumetric technique. Analysis may be undertaken either as a single point BET area or a multipoint BET area measurement with adsorption pressures being selected according to the sample being analysed. The standard report details tabular data with the surface area measurement and the BET surface area plot. All adsorption pressure points are selected so that the BET range of particular samples is covered by the data. The determination of surface area also forms part of our standard report for gas adsorption isotherm data (see the gas adsorption isotherms page via analytical services)

Standard BET Surface area plot

SC13 Test: Multipoint BET Surface Area    SC7Q Test: Single Point BET Surface Area 

SC12 Tests: Multipoint BET Surface Area (Using Krypton)

For the determination of low surface areas (typically lower than about 0.1 m²g) a flowing gas technique is available. Single point surface area and multipoint surface area analyses are available options, with the multipoint technique typically applying 4 adsorption pressures within the BET range. Nitrogen or Krypton may be applied to this technique. 

SC14 Test: Multipoint BET Surface Area (Using Argon or Carbon Dioxide)

MCA Services are able to offer further extensions to surface area analysis, thus covering the most specialised samples by offering comprehensive surface area testing capabilities. Through the application of alternative adsorbate gases, such as krypton, argon and carbon dioxide, very low surface area samples or specialist materials may be successfully analysed. As with our standard testing, these methods also employ the BET area method. 

Standard BET area tabular report

Surface area, or specific surface area, is a critical factor influencing the operation and behaviour of many materials. It is often applicable to such issues as the determination of stability and the efficiency of most materials, including catalysts and pharmaceuticals. The measurement of surface area also provides a critical measurement for quality control of many materials. Our applications page provides more details of the potential uses of the technique.