A strategy to evaluate the surface energy of high packing efficiency fine powders via inverse gas chromatography

- Over-pressuring can be prevent by mixing the samples with silanized carrier particles.
- Critical mass of sample is required to be in the stationary phase.
- Silanized carrier particles do not influence surface energy measurements.

The determination of the surface energy of free-flowing fine powders through IGC analysis can be technically challenging. These powders can have high packing efficiencies that can often lead to excessive gas pressure build up as the mobile phase passes through the stationary phase. As such, free-flowing fine powders may not necessarily be readily suitable to form the stationary phase of an IGC system. To alleviate this challenge, large carrier particles, in the form of silanized glass powders, can be blended with the free-flowing fine powder, in a manner that aids in disrupting the packing efficiency. However, the major concern here is that the introduced foreign material can potentially interfere with the probing of the sample of interest.This research found that blending 250 μm silanized glass beads with a free-flowing fine powder can effectively reduce the pressure build up to prevent the system from over-pressuring. Additionally, it was observed that there is a critical mass for the sample of interest. Below this critical mass, the introduction of the carrier particles can interfere with the determination of the surface energy of the sample, where the surface energy was underestimated. However, above this critical mass, the introduction of the carrier particle does not significantly influence the surface energy determination of the sample of interest. It is therefore concluded that blending free-flowing fine powders with large carrier particles is a potential approach to resolve the challenge of over-pressured systems, provided the mass of the powder of interest is above the critical mass for that powder.

Blending large silanized carrier particles with free-flowing fine powders can prevent over-pressuring of the inverse gas chromatography system.167