Identification of compounds and specific functional groups in the wavelength region 168–330 nm using gas chromatography with UV detection

Abstract

A GC–UV instrumental set up with two different GC units has been used for determination of specific functional groups and compounds in complex mixtures. Separations have been made using a micro gas chromatograph built into a gas flow cell and by means of an external capillary gas chromatograph linked to the same gas flow cell. Four various applications (cigarette smoke, petroleum, dust, flavour) have been performed in order to demonstrate the potential of the GC–UV method. Gas phase UV spectra have been recorded in the region of 168–330 nm. Based on a gas phase spectrum reference library the identification of unknowns as well as the determination of specific functional groups have been achieved. A table showing the spectral shapes and positions of the absorption bands for 50 specific functional groups is presented. The advantage of using derivative spectra in order to amplify spectral details and improve selectivity is discussed. Regarding sensitivity, it has been found that identifications can be made in the mid-pg range and limit of detection for naphthalenes are at a level of 0.5–3 pg/s.