A Solvent Elimination Interface for Capillary Supercritical Fluid Chromatography/Fourier Transform Infrared Spectrometry Using an Infrared Microscope

Abstract

Compounds separated by capillary supercritical fluid chromatography (SFC) are identified by Fourier transform infrared spectrometry (FTIR) using an FTIR microscope and an interface that is based upon rapid elimination of the mobile phase. In this approach to SFC/FTIR, the separated components are directly aspirated onto the surface of a ZnSe window from the end of the restrictor. Since the solutes are deposited out in a very small area, and spectra are measured without any interference from the mobile phase, it is possible to obtain identifiable spectra at the low nanogram level, even for non-optimized depositions. Several of the factors which affect the sensitivity of this type of interface are discussed.