The CryoSync is a deceptively simple device entirely developed by Quantachrome Instruments
(patent pending). This amazingly powerful and affordable cryocooling accessory allows users of Autosorb iQ analyzers and other suitable gas sorption instruments to fulfil the IUPAC recommendations to analyse microporous material using argon rather than nitrogen gas.
Autosorb iQ model with CryoSync Accessory
Argon, unlike nitrogen, has no quadrupole moment. Therefore, its molecules do not tend to orient or pack themselves in special ways in response to interactions with polar surface sites (ions, functional groups, etc.). This means that argon isotherms are sensitive only to surface physical and pore structural features, and not its surface chemistry.
At 87.3 K (liquid argon temperature), experimental conditions are ideal for obtaining full adsorption/desorption isotherms that can be more directly and unambiguously correlated with surface and pore structural features.
IUPAC Technical Report 2015
Published in Pure and Applied Chemistry Volume 87, Issue 9-10 - Physisorption of gases, with special reference to the evaluation of surface area and pore size distribution
“The choice of adsorptive is crucial in the characterisation of porous materials. Nitrogen at 77 K has been widely used, but the interpretation of the isotherm data is not always straightforward. For various reasons, argon adsorption at 87 K is considered to be more reliable and is now recommended – particularly for micropore size analysis”
For more information contact us.