GC/FT-IR Experimental Considerations in the Separation of Complex Hydrocarbon Mixtures Using Fused Silica Columns

Abstract

The successful interfacing and utilization of fused silica capillary GC columns with Fourier transform infrared spectrometry (FT-IR) can introduce difficulties not usually encountered with lower efficiency (higher capacity) GC columns. Recognition of these difficulties, however, can lead to refinement of a GC/FT-IR detection system which can analyze complex samples with low nanogram detection limits. Chromatographic and spectrometric considerations include lightpipe temperature, choice of sample introduction, column concentration dynamic range capability, infrared data acquisition rate, and spectral S/N ratio. These parameters as they relate to capillary GC/FT-IR method development are discussed. The GC/FT-IR analysis of a complex sample is presented in an effort to explain these problems. In order to reflect the FT-IR sensitivity under complex sample chromatographic conditions, quantification data using known compounds are also included.