Validation of immunoassay methods to determine hydrocarbon contamination in estuarine sediments

Abstract

The performance of two commercially available enzyme-linked immunosorbent assay (ELISA) kits (with antibodies attached to magnetic particles) for quantification of hydrocarbons in estuarine sediments is described. The BTEX RaPID Assay® was employed to analyse aliphatic and small aromatic hydrocarbons whilst the c-PAH RaPID Assay® was used to analyse the carcinogenic (≥ 4 aromatic rings) polycyclic aromatic hydrocarbons. Results were validated by comparison with analyses by gas chromatography (GC)- Flame Ionisation Detection (FID) (with GC-MS confirmation). Correlations between the techniques were good with r2 values ranging between 0.68 and 0.97. Disparity between immunoassay and GC techniques were related to differences in the relative compositions of the complex mixtures of hydrocarbons, which alter ELISA responses. Overall, results from the ELISA techniques are shown to compare well with those obtained by GC, confirming ELISA as a useful screening protocol to focus use of the more expensive and time consuming high resolution analytical techniques. ©2007 Sociedade Brasileira de Química.