The detection and determination of polynuclear aromatic hydrocarbons by luminescence spectrometry utilising the Shpol'skii effect at 77 K

Abstract

The luminescence emission spectra of twenty-three polynuclear aromatic hydrocarbons (PAH) have been examined in n-alkane solvents at 77 K. The Shpol'skii effect, in which narrow-band (quasi-linear) emission spectra are obtained under these conditions when a monochromator of adequate resolving power is used, is shown to be readily observed for twelve of the compounds examined in these solvents. Quasi-linear emission spectra have also been obtained in tetrahydrofuran for some of the PAH compounds examined. These emission spectra provide for unambiguous qualitative identification of PAH compounds at trace concentrations in solution; this effect is demonstrated by identification of the compounds present in an eight-component mixture of PAH compounds.

Measurement of the low-temperature quasi-linear luminescence intensity can be applied quantitatively to the determination of these compounds provided that a standard additions procedure is employed in conjunction with the use of an internal standard to ensure sufficient accuracy and precision.