REVERSED-PHASE LIQUID-CHROMATOGRAPHY FOURIER-TRANSFORM INFRARED SPECTROMETRY USING CONCENTRIC FLOW NEBULIZATION

A novel technique for interfacing a microbore reversed-phase high-performance liquid chromatograph and Fourier transform infrared (FT-IR) spectrometer has been developed. Warm hellum gas is passed through the outer of two concentric fused-sillca tubes while the effluent from a liquid chromatograph is passed through the inner tube. The tubes are housed in a vacuum chamber equipped with a rotatable stage used for solute deposition. With this approach, solute spots less than 150-mu-m in diameter can be obtained from aqueous mobile phases. In this feasibility study, a two-step procedure was developed in which transmission spectra of the deposited solutes are measured by using an FT-IR microscope after the solutes have been deposited onto a ZnSe plate. Complete elimination of the solvent from a mobile phase containing up to 100% water at a flow rate of at least 50-mu-L/min is possible. The minimum identifiable quantity in a measurement time of 45 s is less than 500 pg. On-line measurements using the same technique are shown to be feasible.