On-line coupling of liquid chromatography to thin-layer chromatography for the identification of polycyclic aromatic hydrocarbons in marine sediment by fluorescence excitation and emission spectroscopy

Abstract

Storage of the effluent from a reversed-phase column liquid chromatography separation on a thin-layer chromatography plate offers two advantages: (1) detection principles that are not applicable on-line with flow systems can be used; (2) the thin-layer chromatography plate itself allows a second separation to be carried out. Both advantages are demonstrated for the separation and identification of polycyclic aromatic hydrocarbons in a marine sediment sample. The effluent from a microbore liquid chromatography column was deposited on a linearly moving thin-layer chromatography plate through a spray jet assembly interface. As with isocratic liquid chromatography, not all polycyclic aromatic hydrocarbons present in the sample could be separated; a second separation of the immobilized chromatogram was applied by means of thin-layer chromatography. The overlapping peaks were then resolved completely. Eleven polycyclic aromatic hydrocarbons were identified by measuring their fluorescence excitation and emission spectra on the thin-layer chromatography plate with a conventional spectrometer.