PNNL

Abstract

The purpose of this research was to investigate coating capillary columns with lanthanide(III) beta-diketonate polymers to provide gas-chromatographic columns with selectivity toward explosives and related compounds. Capillary columns were statically coated with a combination of a lanthanide(III) beta-diketonate polymer, which utilized p-di(4,4,5,5,6,6,6-heptafluoro-1,3-hexanedionyl)benzene (dihed) as a ligand, and SE-30. A novel coating technique was developed that used a methanol-containing azeotrope to provide solubility for both polymers while maintaining a low boiling point compatible with static coating. As based on temperature-programmed retention indices, the custom experimental columns displayed selective retention of nitroaromatic, nitroalkane, and nitrate ester test probes relative to an appropriate SE-30 control column. Selective retention was more pronounced for strong Lewis base analytes (i.e., cyclohexanone). Relative analyte retention on the La(dihed), Tb(dihed) and Eu(dihed) columns are discussed relative to Lewis acidity and solubility of the polymer in the azeotrope coating solution.