Separation of Lanthanide β-Diketonates via Organophosphorus Adduct Formation by Supercritical Fluid Chromatography

Abstract

This paper describes a novel method for separation and detection of lanthanide β-diketonates by adduct formation/supercritical fluid chromatography (SFC) with an open-tubular capillary column and a FID detector. Separation of lanthanide β-diketonates cannot be achieved by SFC due to the hydration of the complexes, which exhibit strong intermolecular interactions and decomposition in the system. Formation of adducts of lanthanide β-diketonates with a neutral donor, tributylphosphine oxide (TBPO) or trioctylphosphine oxide (TOPO), alters their SFC behavior. The adduct formation approach leads to the first successful separation of lanthanide complexes of the same β-diketone ligand by SFC using neat CO2 as the mobile phase.