HIGH-TEMPERATURE WATER EXTRACTION COMBINED WITH SOLID-PHASE MICROEXTRACTION

Solid phase microextraction (SPME) was coupled with high temperature w ater extraction for the determination of non-polar semivolatile compou nds in solid matrices, Two different SPME approaches, dynamic and stat ic, are described, In the dynamic extraction technique, analytes leach ed by hot water from a matrix were collected in a vial and simultaneou sly extracted from the water with SPME fibre, The collection vial was cooled using a bath to avoid analyte loss by evaporation, The optimize d method using water extraction and SPME allowed quantitation based on external calibration with polycyclic aromatic hydrocarbons (PAHs) ext racted from spiked sand, In the static approach, the water extraction of solids was performed using a high pressure cell with an SPME fibre inserted in the vessel, During the extraction process analytes were re leased from the matrix and then partitioned into the fibre coating as the cell was cooling down, In this technique isotopically labeled anal ogs of target analytes were used to compensate for the partial re-adso rption of analytes on the solid matrix at lower temperatures, The effe cts of different experimental conditions on the static high temperatur e water-SPME fibre extraction of NIST certified reference material, ur ban air particulates, were investigated, For quantitation the SPME fib re was removed from the collection water or the high pressure cell, an d was immediately transferred to a gas chromatograph injection port to analyse extracts without any clean-up or pre-concentration. Both meth ods enable the determination of PAHs in solid matrices without use of organic solvent, Static high temperature water-SPME has an additional advantage since it does not require a high pressure pumping system.