Our first online webinar "Introduction to Inverse Gas Chromatography (IGC) and Best Practice" on 8th June 2020 was a great success. More than 45 participants participated and actively engaged in the Q&A session. The initial objective of the webinar was to give newcomers in IGC a first understanding in this technology as a preparation for to 9th Int. IGC Symposium, 16th June 2020, see IGC Symposium website.
However, it seems, it was the beginning of an open, almost global dialogue about how to characterize powder and other surfaces by dynamic gas adsorption.
Summary of Introduction into Inverse Gas Chromatography
The webinar offered a brief, but concise overview in surface characterization of powders, fibres and even films by dynamic gas adsorption using 15 and more “gas probes” to “sense” the surface, also called Inverse Gas Chromatography (IGC).
Depending on the character of the gas probes, different parameters are obtained – quantitatively, sensitive and reproducible. The series of n-alkanes, e.g. hexane, heptane, octane, … provides the disperse surface energy 𝛾sd. The use of branched and cyclic alkanes provides information of a kind of nanoroughness either by exclusion of the bulkier probes compared to linear n-alkanes or by a kind of solubility by cyclic alkanes, characteristic for amorphous phases or organic coatings.
Several polar probes, ranging from chloroform to diethylether provide not only an overall specific polarity, but also an indication about the electron acceptor and donor properties, i.e. the Lewis acid and base character of the unknown surfaces.
The heterogeneity of the surface can be determined by saturating the surface at a defined p/p0 of a chosen probe molecule and interpretation of the desorption profile. The method provides not only the Adsorption Energy Distribution Function, but also the specific surface area, S(BET).
Many advices on best practices, like the preparation of the samples or the concentration range of gas probes, are provided too.
During the webinar we mentioned different resources. Below you find the links for the participants or those, who are interested in the technology as such:
You can download the presentation of the webinar below.
The Q&A session after the presentation highlighted many open questions and uncertainties around IGC as a technique. You find the questions and some of the answers below. We plan to answer them in a separate blog post. Follow us and stay tuned.