Use of Buffered Solvent Systems with Concentric Flow Nebulization Liquid Chromatography/Fourier Transform Infrared Spectrometry

Abstract

Identifiable Fourier transform infrared (FT-IR) spectra of species eluting from a high-performance liquid Chromatograph (HPLC) in buffered mobile phases are shown. The spectra are measured with the use of an online solvent-elimination HPLC/FT-IR interface based on direct-deposition concentric flow nebulization. Both volatile and nonvolatile buffers were used, in mobile phases consisting of 63–100% water. Examples of spectra of components separated by microbore HPLC using these buffered systems are shown. For the systems using nonvolatile buffers, spectral subtraction is needed to obtain analyte spectra, and absorption bands due to the buffer are rarely completely eliminated. For systems using volatile buffers, very little or no spectral subtraction is needed at low buffer concentrations. Minimum identifiable quantities in the low-nanogram range were achieved.