Application of magnetic iron oxide nanoparticles for the analysis of PCBs in water and soil leachates by gas chromatography-tandem mass spectrometry.

Two magnetic solid-phase extraction methods (mSPE) were developed and compared for the extraction and preconcentration of polychlorinated biphenyls (PCBs) from water and soil leachates. Analyses were carried out by gas chromatography coupled to triple quadrupole mass spectrometry. The mSPE extraction parameters were optimised using Fe3O4 nanoparticles coated with palmitate or oleate. Differences were found between the developed mSPE methods depending on the magnetic nanoparticle coating. The extraction efficiency of both sorbents was studied by spiking soil leachates at three concentration levels (from 0.6 to 0.18 ng ml(-1) and from 0.4 to 0.04 ng ml(-1) using palmitate or oleate coated nanoparticles, respectively) and recoveries from 86 to 109 % were obtained. The developed method provided a preconcentration factor of 250. The detection limits were about 29 times lower with the oleate-coated nanoparticles. Although both mSPE procedures could be used for the extraction of PCBs from water and soil leachates, oleate-coated nanoparticles gave the best extractive conditions and lower quantifications limits. Finally, the mSPE using oleate-coated nanoparticles was applied to the analysis of PCBs in river waters and in soil leachates obtained from soil with different physico-chemical characteristics. The levels of PCBs present in the leachates depended on the soil sample. The present work demonstrates the applicability of both mSPE methods to the determination of PCBs in water and soil leachates, which is of interest for mobility and bioavailability studies of these compounds in soil.