Inverse Gas Chromatography (iGC) is a gas-solid technique for characterizing surface and bulk properties of powders, particulates, fibers, films and semi solids.
A series of vapor pulses are injected through a column packed with the sample of interest. Unlike traditional analytical gas chromatography, iGC is a physical chemistry technique using vapor probes with known properties to characterize the unknown surface/ bulk properties of the solid sample.
Founding Principle of iGC-SEA
An experiment consists of a series of vapor pulses or frontal injections eluting through a column packed with the sample under examination.
A pulse of constant concentration of gas is then injected down the column at a fixed carrier gas flow rate, and the time taken for the pulse or concentration front to elute down the column is measured by a detector. A series of IGC measurements with different gas phase probe molecules then allows access to a wide range of phyisco-chemical properties of the solid sample.
The injected gas molecules passing over the material adsorb on the surface with a partition coefficient KS:
Ks = Vn / Ws
Where VN is the net retention volume – the volume of carrier gas required to elute the injection through the column, and WS is the mass of the sample. VN is a measure of how strongly the probe gas interacts with the solid sample and is the fundamental data obtained from an IGC experiment; from it a wide range of surface and bulk properties can be calculated.
iGC- SEA or Inverse Gas Chromatography-Surface Energy Analyzer
It is an instrument that uses the iGC principle. The heart of its innovation is the patented injection manifold system which generates accurate solvent pulse sizes across a large concentration range, resulting in isotherms at unprecedented high and low sample surface coverages. This allows for the accurate determination of surface energy heterogeneity distributions. The fully automated iGC-SEA can be operated at different solvent vapor, flow rate, temperature, humidity and column conditions.
iGC-SEA has a unique data analysis software called Cirrus Plus, specifically designed to measure surface energy heterogeneity, isotherm properties and related physical characterization parameters. Further, bulk solid property experiments resulting from probe-bulk interaction and using solubility theory are now possible. It automatically and directly provides a wide range of surface and bulk properties of the solid samples and gives more accurate and reliable data than manual calculations. It also has a humidity control option. The impact of humidity and temperature can be determined for the physicochemical properties of solids such as moisture induced Tg, BET specific surface area, surface energy, wettability, adhesion and cohesion. Read product information or request application notes.