Simultaneous Determination of C,H,N,O,F,Cl,Br,and S in Gas Chromatographic Effluent by Fourier Transform Red/Near-Infrared Atomic Emission Spectroscopy

Abstract

A high-powered, atmospheric-pressure, helium microwave-induced plasma (MIP) is used as the interface between a gas chromatograph (GC) and a Fourier transform near-infrared (FT-NIR) emission spectrometer. By the collection of a series of time-resolved interferograms when organic compounds elute from the GC into the plasma, a complete account of both spectral and chromatographic activity is recorded. Computer-generated, element-specific chromatographic reconstructions for each of eight different nonmetals are obtained from a single injection of a chemical mixture. Atomic emission intensity vs. chromatographic retention time is plotted for each of eight or more optical frequencies chosen from the 15,700–7900 cm⁻¹ region. The frequencies are preselected to coincide with spectral lines of C, H, N, O, F, Cl, Br, and S emitting from the helium MIP. This unique GC/MIP/FT-NIR emission spectrometer provides simultaneous multielement-specific chromatographic detection of a variety of nonmetals important to synthetic organic chemistry.