Coupling superheated water extraction with enzyme immunoassay for an efficient and fast PAH screening in soil

The coupling of an enzyme immunoassay with a superheated water extraction is an attractive technique because of the reduced use of hazardous solvents, due to their hostile impact on the environment. This paper describes the use of superheated water extraction and enzyme immunoassay (EIA) for the determination of polycyclic aromatic hydrocarbons (PAHs) in native (not spiked) surface soil and sediment samples. The extraction recoveries with superheated water were comparable to those achieved with conventional Soxhlet techniques. The benefits of superheated water extraction-EIA includes replacement of harmful organic solvents used in extraction, fast extractions (15-30 min.) with an inexpensive extractant, reduced number of steps in the determination of the target compounds, and the application of sensitive and relatively inexpensive assays. Further advantages of the superheated water extraction are higher extraction efficiencies compared with the methanol based extraction kits associated with the EIA and direct measurement of the extracts with EIA. Both techniques can be used as efficient screening methods in the field since the type of equipment used in superheated water extraction and EIA can be loaded into a van and operated on a car battery or a small generator. (C) 1998 Elsevier Science B.V. All rights reserved.