Determination of Polycyclic Aromatic Hydrocarbons in Waxes by High Performance Liquid Chromatography with Fluorimetric Detection

Abstract: A method for the determination of polycyclic aromatic hydrocarbons (PAHs) at the ppb level in waxes has been developed. It consists of single extraction of the aromatic fraction from 5 g of melted wax into 40 mL of acetonitrile, followed by partial evaporation of the solvent. Quantification of PAHs was performed by HPLC with fluorimetric detection (HPLC-FL) using two-channel programmable excitation and emission wavelengths. On-column limits of detection (LODs) were 0.1–1 pg. The average recovery of PAHs was 68%. Calculated LODs of PAHs in wax samples were 3–23 μg/kg. No interferences of small amounts of wax were observed during the FL detection. Selection of the best solvent was made by means of the Chemcad simulation of the extraction process. The most promising systems were verified experimentally. Other detection modes, such as ultraviolet, gas chromatography−mass spectrometric and gas chromatography with flame ionization, were compared with the proposed HPLC-FL.