Universal Calibration Method for the Determination of Polycyclic Aromatic Hydrocarbons by High Performance Liquid Chromatography with Broadband Diode-Array Detection

The response of polycyclic aromatic hydrocarbons (PAH) at different UV wavelengths was measured using high performance liquid chromatography with spectrophotometric diode-array detection. By utilizing the total UV absorption bandwidth (200-400 nm), it was found that a narrow distribution of normalized response factors (area/g) could be obtained for 16 PAH in a reference mixture of frequently-occurring species, even though the PAH represented a wide variety of different chromophores. Using the mean response factor for the 16 PAH, a universal calibration factor was obtained that formed the basis of a method for the determination of PAH for which calibration data cannot otherwise be obtained. It utilized normal phase high performance liquid chromatography (HPLC) with a cyanopropyl column and a hexane-dichloromethane mobile phase. The HPLC conditions were optimized for the separation of PAH according to their aromatic ring number. The method was developed for the characterization of complex mixtures of fossil fuels-derived PAH that cannot be analyzed by traditional methods. It is applicable to PAH having from 1 to 10 or more fused aromatic rings.