SOLID-PHASE EXTRACTION OF POLYCYCLIC AROMATIC-HYDROCARBONS FROM SOIL SAMPLES

A new solid-phase extraction (SPE) method was developed for the analysis of 16 polyaromatic hydrocarbons (PAHs) on the US Environmental Protection Agency priority list, in soil samples. Different types of SPE columns were tested and conditioning and elution steps were optimised. In the final procedure, soil samples are extracted with acetone and, after dilution with HPLC-grade water, loaded on a C-8 SPE column. After washing, all PAHs are eluted with tetrahydrofuran (THF). The final THF extract is analysed on an HPLC system for PAHs. Recoveries of the volatile PAHs, naphthalene, acenaphthylene and acenaphthene were 80-90%. All other recoveries are comparable with standard liquid-liquid extraction (LLE) and range from 75 to 90%. The method is compared with the conventional LLE method for different types of real soil samples of a Dutch monitoring programme. Results indicate that SPE is a good method for the sample preparation for the analysis of PAHs in soil samples. Compared with LLE, correlation coefficients are better than 0.9 with relative standard deviations for SPE between 0.8 and 9.1%. LLE standard deviations ranged from 1.1 to 15.1%.