A Chromatographic procedure for the comprehensive separation and estimation of polycyclic aromatic hydrocarbons in petroleum products

Abstract

A Chromatographic procedure using liquid and gas chromatography for the determination of both total and certain individual 4–6-ring polycyclic aromatic hydrocarbons from a single sample aliquot is described. The sample, spiked with known amounts of internal standards is fractionated using adsorption chromatography over water-deactivated silica gel followed by preparative normal-phase high-performance liquid chromatography (h.p.l.c.) on amino-bonded silica gel to give a total 4–6-ring polycyclic aromatic (PCA) fraction. The total PCA content of the sample is determined gravimetrically. This fraction is subsequently further fractionated on Sephadex LH20 to give one rich in PCA parent hydrocarbons which are determined using high-resolution capillary gas chromatography (g.c.). The compounds of interest are quantified by comparison of their g.c. peak areas with those from secondary internal standards. The results are corrected for losses occurring during the analysis by determining the recovery of an internal standard using ultraviolet (u.v.) spectroscopy. The total PCA determination, which may be performed on formulated oils without interference from the chemical additives, has a lower level of detection of 0.1 wt% whereas that of the individual analyses is 0.1 mg kg −1. The analysis scheme may be applied to a wide range of sample types. The complete analysis can be performed in one working day.