Abstract

A study has been carried out on the applicability of cryotrapping gas chromatography-Fourier Transform infrared spectrometry (GC-FTIR) for the identification and isomer discrimination of polycyclic aromatic hydrocarbons (PAHs). Method development has been performed by means of a standard mixture of 24 PAHs of the series from naphthalene to benzo(ghi)perylene. All compounds including structural isomers have been identified on the basis of spectral differences. Detection limits were established as 250-500 picogram per microliter injected on-column. The applicability of the method has been tested on the analysis of sediment, soil and river clay extracts, which had been analysed previously by means of HPLC with fluorescence detection. The presence of the majority of the PAHs was unequivocally confirmed while previously undetermined PAHs could be identified. Moreover essential additional information was obtained on the identity of two coeluting structural isomers. As such cryotrapping GC-FTIR forms an important additional tool in the analysis of PAHs by means of GC-FID, GC-MSD and HPLC with fluorescense detection. Cryotrapping spectra of PAH appear to be quite similar to conventionally recorded spectra. Absorption frequencies are found within the data point resolution although minor intensity differences may occur. For that reason existing interpretation and library search systems remain useful for structural elucidation.