Evaluation of QuEChERS approach for the analysis of polycyclic aromatic hydrocarbons in sediments

Polycyclic aromatic hydrocarbons (PAHs) are mainly produced as by-products from the incomplete combustion of organic matter and fossil fuel. They constitute ubiquitous environmental contaminants and are of main concern since their toxicities have been widely demonstrated (carcinogenic and/or mutagenic properties notably). Regarding aquatic environment, they have been included in the list of priority substances as defined by the European Union Water Framework Directive. Their monitoring is therefore mandatory to assess the quality of aquatic media. The PAH are hydrophobic component so are mostly adsorbed onto sediments. Extraction using pressurized fluid is the most popular method for sediment sample treatment. It is very efficient for extracting the target analytes but also all the other potentially interfering components that might be present within the matrix. Moreover, this technique is relatively expensive since dedicated equipment is needed. The QuEChERS approach, developed initially for the analysis of pesticides in fruits and vegetables, can be regarded as an alternative technique to simplify this step. It is easy to handle, relatively cheap and with low solvent consumption. Therefore, this technique has been evaluated in this study for the extraction and sample treatment of PAH in sediments. The analysis of PAH was then performed by gas chromatography coupled to mass spectrometry. A QuEChERS type method and purification protocol based on the approach generally carried out for fruits and vegetables was applied. An extraction with vortex agitation using acetonitrile was performed followed by a purification step by dispersive solid phase extraction. Extraction parameters such as agitation time were investigated. Influence of water addition to sediments was determined as a particularly significant parameter on recoveries of PAH. The purification step was also evaluated with the test of several phases. Finally, the optimized protocol was tested on several sediments and on reference certified materials. Overall, in most cases, the QuEChERS based approach appeared suitable for the analysis of PAH in sediments