The continuous infrared spectroscopic analysis of reversed phase liquid chromatography separations

Abstract

A method for HPLC/FTIR is discussed in which the effluent from a microbore HPLC is continuously deposited onto and eliminated from the surface of a circular rotating germanium crystal that has been aluminum coated on its opposite side. After deposition, the germanium disk is again rotated, this time in the sample compartment of an FTIR spectrometer while reflectance-absorbance infrared spectra are continuously collected. The novel germanium-aluminum deposition surface allows collection of reflectance-absorbance spectra that are free of the degrading effects of superposition phenomena characteristic of reflectance-absorbance spectra obtained on metal surfaces. Furthermore, germanium is impervious to aqueous solvent mixtures and, therefore, allows for the direct deposition of reversed phase separations, including those requiring acid modified mobile phases.