Determination of polycyclic aromatic hydrocarbons in contaminated water and soil samples by immunological and chromatographic methods

An immunoassay was developed that can be used for the detection of polycyclic aromatic hydrocarbons (PAHs) in water, landfill leachate, and soil. As test format an indirect competitive microtiter plate ELISA (enzyme- linked immunosorbent assay) was applied. While groundwater samples from a former manufactured gas plant site could be analyzed directly, soil and landfill leachate had to be extracted and required at least a 100-fold dilution prior to immunochemical measurement. PAHs could be recovered from fortified reference soils as well as aged field samples with high yield using 1-h ultrasonication with acetonitrile. Extraction efficiency was comparable to Soxhlet extraction and ultrasonication with tetrahydrofurane. Recovery was lower with agitation but would still be acceptable for use in an on-site field test to provide rapid, semiquantitative, and reliable test results for making environmental decisions such as identifying 'hot spots', site mapping, monitoring of remediation processes, and selecting site samples for laboratory analysis. Classification of ELISA data showed that it was possible to estimate the PAH contamination in soils with about 5% false positive and 5% false negative results that may have arisen from heterogeneity of samples, cross-reactivity of compounds with a similar structure, humic acids, or unknown interferences.