Determining Polychlorinated Biphenyls in Soil Using Accelerated Solvent Extraction (ASE)

Contamination of the environment with compounds belonging to the persistent organic pollutants (POPs) group constitutes a global problem. According to the Stockholm Convention adopted in 2001, much effort should be put into the minimisation of its presence not only in soil, water, and residues, but also in living organisms where these compounds are accumulated. As a consequence of research conducted in the area of environmental matrices involving wide ranges of chemical compounds, a growing demand for various certified reference materials has been observed. This study was focused on finding the most efficient extraction conditions for six polychlorinated biphenyl congeners: Nos. 28, 52, 101, 138, 153, and 180, with the accelerated solvent extraction (ASE) method and with the use of CRM963 manufactured by RTC. Analyte recovery was examined by the application of the following solvents: hexane, hexane/acetone, and acetone/dichloromethane at 150 degrees C and 170 degrees C. The best recovery (88.5-106%) and the lowest standard deviation (2.1-5.7%) values were obtained for hexane at 170 degrees C. The method was further employed to determine the homogeneity and stability of soil being the candidate for CRM. Moisture and organic carbon content in both the CRM963 as well as the soil examined were determined.