Sample-Inlet System for Studying Adsorption of Low Vapor Pressure Materials on Solid Surfaces

Abstract

Infrared spectroscopy has not been extensively used to study vapor-phase adsorption of low volatility liquids or solids on solid surfaces. This is almost certainly because of the difficulties involved in introducing these samples into the cell in such a way that they can interact with an activated solid (catalytic) surface. In this type of application, it is necessary to devise a sample-inlet system which has a small volume, is operable at temperatures up to 200°C, is evacuable to 10⁻⁵ Torr, and will not interfere with the high temperature (500°C) oxidation (1 atm O₂) or high vacuum (10⁻⁵–10⁻⁶ Torr) pretreatment of the catalytic surface. That is to say, the inlet system must be an extension of the adsorption cell itself.