Liquid chromatography analysis of phosphonic acids on porous graphitic carbon stationary phase with evaporative light-scattering and mass spectrometry detection.

The analysis of several phosphonic acids has been investigated by liquid chromatography (LC), using porous graphitic carbon as stationary phase with mass spectrometry (MS) or evaporative light-scattering detection (ELSD). In both detection modes (MS and ELSD), the mobile phase must be volatile and, due to the porous graphitic carbon (PGC) properties, should promote electronic interactions. Among the various hydrogeno- and perfluorocarboxylic acids tested, trifluoroacetic acid (0.1%, v/v) was selected as electronic competitor for solute retention. The baseline resolution of a phosphonic acids mixture required a trifluoroacetic-acetonitrile gradient elution. This methodology was then applied to the identification of phosphonic acids in a spiked tap water sample. Quantitative analyses are successfully achieved with a good correlation coefficient.