On the semi-quantification of polycyclic aromatic hydrocarbons in contaminated soil by an enzyme-linked immunosorbent assay kit

Polycyclic aromatic hydrocarbons (PAHs) are of environmental concern, for instance when found in contaminated soils at sites where industrial activities have occurred. For efficient screening of such soils, the commercially available enzyme-linked immunosorbent assay (ELISA) kit, the PAH RISc® soil test, can be used. However, the site-specific performance may vary due to differences in soil properties and contamination profiles. Hence, in this study we have examined various contributing factors to the total ELISA measurements uncertainties. These factors include contributions from co-extracted (non-target) compounds, the extraction efficiency and differences in cross-reactivity among the target analytes. Reference values were obtained through pressurized liquid extraction (PLE) and gas chromatography coupled to mass spectrometry (GC–MS) analysis. The results showed that the ELISA does not seem to respond to non-target compounds in the soil extracts to any large extent. Furthermore, high molecular weight PAHs were found to be more efficiently extracted with PLE than with methanol agitation, which is used for ELISA. If this, and the cross-reactivity of the individual PAHs, were taken into consideration, the ELISA and GC–MS results were in good agreement.