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 extract ion 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 immunoass ay (EIA) for the determination of polycyclic aromatic hydrocarbons (PA Hs) in native (not spiked) surface soil and sediment samples. The extr action recoveries with superheated water were comparable to those achi eved 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 targe t compounds, and the application of sensitive and relatively inexpensi ve assays. Further advantages of the superheated water extraction are higher extraction efficiencies compared with the methanol based extrac tion kits associated with the EIA and direct measurement of the extrac ts with EIA. Both techniques can be used as efficient screening method s in the field since the type of equipment used in superheated water e xtraction and EIA can be loaded into a van and operated on a car batte ry or a small generator. (C) 1998 Elsevier Science B.V. All rights res erved.