Systematic approach to coupled gas chromatography Fourier transform infrared spectroscopy using two wide bore capillary columns

Abstract

The approach to coupled gas chromatography Fourier transform infrared spectroscopy (GC-FTIR) described in this paper is designed to achieve good separation with pre-set column parameters, allowing fast and precise identification of the components. For this reason the sample is separated on a gas chromatograph fitted with two wide bore (530 µm) capillary columns of different polarities. The use of two columns allows a definite statement about the number of components in the mixture to be made. Infrared (IR) spectra can then simply be taken from the centre of each peak. The wide bore capillary columns were necessary to achieve the desired peak volume, peak shape and sample loading to match the light pipe volume. Temperature gradients were developed which kept the peak width constant and relatively narrow throughout the separation, thus maximising the concentration of components passing through the IR cell. This systematic approach provides a methodology for the technique, which, if adopted, would result in an increased sample throughput and greater reliability.