Multiresidue analysis of aromatic organochlorines in soil by gas chromatography-mass spectrometry and QuEChERS extraction based on water/dichloromethane partitioning. Comparison with accelerated solvent extraction.
Résumé
A novel multiresidue method was developed for the simultaneous analysis of 34 organochlorines, including chlorobenzenes, chlorophenols, chlorinated hydrocarbons and chlorinated olefins, in soil by GC-MS, using a QuEChERS-based extraction. The conventional QuEChERS method was optimised and, for the first time, the use of a non miscible-water solvent was required. The method was compared to ASE extraction, versatile technique widely used for the soils' extraction and QuEChERS-based method was shown to be the most efficient in terms of recoveries, simplicity and rapidity. For ASE, recoveries between 42% and 85% were obtained for the majority of the compounds. However, due to the high pressure, all volatile compounds were lost. In opposite, QuEChERS extraction allowed detection and quantification of all the compounds with recoveries between 60% and 100%. Moreover, no additional clean up by dispersive SPE on PSA was necessary, which allowed reducing the cost of the analysis. Performance of the method was assessed. The method was linear over the range of concentration of 10-5000 μg kg−1. Precision, expressed as intra-day precision and inter-day variation was verified at three concentrations. Limits of detection were from 2 to 50 μg kg−1 and limits of quantification from 7 to 170 μg kg−1 for the majority of the compounds (chlorobenzenes and chlorinated hydrocarbons and olefins), except for chlorophenols. The method was further applied to different soils coming from a contaminated industrial site, where a new environmental remediation process, using phytoremediation, was tested. The results showed that the method could be applied to any kind of soils (mineral or organic) and was appropriate to very volatile compounds which were not available with conventional technique.