Optimization of the QuEChERS extraction procedure for the determination of polycyclic aromatic hydrocarbons in soil by gas chromatography-mass spectrometry

Polycyclic aromatic hydrocarbons (PAHs) are listed as pollutants of great concern and the development of fast and reliable analytical procedures is a modern day challenge. The aim of this study was to optimize the QuEChERS (Quick, Easy, Cheap, Effective, Rugged and Safe) technique, in order to establish an efficient method for the extraction of 16 priority PAHs from soil, using various sorbent and solvent system combinations, followed by GC-MS analysis. The best results were obtained using acetonitrile/water as the extraction solvent and diatomaceous earth as the dispersive solid phase extraction sorbent. The proposed method is rapid, accurate, precise, as well as much cheaper and simpler than other methods used for the extraction of PAHs from soil. The optimized method was successfully applied on real soil samples from an urban area of Nis, Serbia. Analysis of real soil samples showed contamination of soil with mostly light PAHs, where acenaphthene was predominant. The content of total PAHs varied from 345.65 to 27 314.30 mu g kg(-1), with a mean of 3646.39 mu g kg(-1). Only three samples contained elevated amounts of PAHs according the Gazette of the Republic of Serbia.