Flow, thermoconductivity methods

Lobenstein and Dietz deveioped an apparatus not requiring a vacuum system [161]. They adsorbed nitrogen from a mixture of nitrogen and helium in two burettes by continuously raising and lowering attached mercury columns. Equilibrium was established when constant pressure was attained. Additional points were obtained by adding more nitrogen to the system. 

The method, a modification of gas adsorption chromatography in which the column packing is the sample itself and the mobile gas phase is a mixture of a suitable adsorbate and an inert gas, was further developed by Nelson and Eggertsen [162]. They used nitrogen as the adsorbate and helium as the carrier gas. They also used cathetometers to improve accuracy. 

Calibration for such a system may be absolute (by injecting a known amount of adsorbate into the mobile phase at the point normally 

The mobile phase was first passed through the reference arm of the thermal conductivity cell on to the sample and then to the measurement arm of the thermal conductivity ceU. 

Nelson and Eggertsen measured adsorption at three concentrations i.e. three partial pressures. The sample was outgassed at the desired 

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