2.2 Extraction process

Contaminated soil (1g) was mixed with Hydromatrix concentrate (Varian, UK) at a ratio of 1:1 w/w. The mix was then ground vigorously to such an extent that it appeared dry and powdery. The sample was then added to 22 ml stainless steel extraction vial (Dionex, UK) partitioned with disposable cellulose filters (Dionex, 52 UK) and acid washed sand (VWR, UK). Accelerated solvent extractor (ASE) 200 (Dionex, UK) was utilised to perform the extraction process by using Dionex method 324. To facilitate the extraction process, the ASE cell is left in an ASE carousel. Whilst extraction takes place, hexane/acetone, 1:1 (Fisher Scientific, UK) was introduced into the extraction cell up to 50 ml. Upon extraction, the extract was flushed out of the cell into a collection vial with the help of nitrogen, to be analysed. GC-MS was utilised to perform the analysis on the extract. Then, 1.5 ml of the specimen solution was pipetted into the GC auto sampler vial (Technopath, UK) and capped by crimp caps.