New alumina-based PLOT column for high resolution separation of CFC / Refrigerants

Last Capillary symposium in Riva del Garda, a poster was presented on a new PLOT column for CFC analysis.

Chloro-Fluoro Carbons (CFC), also known as Refrigerants or Propellants, are highly volatile compounds which can be analyzed via gas chromatography. There production, application and especially release is controlled carefully as they have a direct impact on the ozone layer. For the separation via GC, we meet some challenges as due to their volatility, a stationary phase is required with very high retention. In gas liquid separations films up to 10 micrometer can be coated, but such thick-films coated columns have low efficiency, due to the huge contribution to mass transfer in the liquid phase.

A more elegant solution is to use adsorbents for the separation.  Alumina coated PLOT columns were developed and applied already 25 years ago with limited success due to high activity of the alumina materials used. Porous polymers also did not provide the correct selectivity and showed severe band broadening.

The use of alumina was recently revisited for hydrocarbon separations and during this project a procedure was developed to reduce the activity of the alumina significantly, making this adsorption material applicable for a large range of CFC type compounds.  The Rt AluminaBOND - CFC columns elutes a wide range of halogenated compounds and showed very promising for the analysis of CFC compounds. All CFC compounds tested did not show any reactivity.

Despite of the huge improvement, there is still some remaining activity for several halogenated compounds, like 1,2 dichloroethane and chloropropane.