Validation of immunoassay methods to determine hydrocarbon contamination in estuarine sediments

Abstract

O desempenho de dois kits comerciais de ensaios imunológicos (ELISA com anticorpos ligados a partículas magnéticas) foi avaliado para a quantificação de hidrocarbonetos em sedimentos estuarinos. O kit BTEX RaPID Assay ® foi utilizado para analisar hidrocarbonetos alifáticos e aromáticos leves, enquanto que o kit c-PAH RaPID Assay ® foi utilizado para hidrocarbonetos poliaromáticos carcinogênicos (≥ 4 anéis aromáticos). Os resultados foram validados comparando com análises feitas por cromatografia gasosa com detectores de ionização de chama (GC/DIC) e de espectrometria de massa (GC/EM). Foi observada uma boa correlação entre as técnicas (r 2 =0,68-0,97), estando a disparidade relacionada a diferenças na composição relativa de hidrocarbonetos que afeta a resposta dos anticorpos dos testes ELISA. De uma forma geral, os resultados obtidos com os kits ELISA foram comparáveis aos obtidos por cromatografia, confirmando a validade dessa técnica em protocolos de avaliação preliminar, visando o emprego de técnicas analíticas de alta resolução em amostras específicas.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 r 2 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.Keywords: immunoassay, ELISA, hydrocarbons, PAHs, validation, sediment IntroductionAliphatic and aromatic hydrocarbons are amongst the most commonly detected contaminants in the aquatic environment, deriving from petroleum and combustion processes. Their ubiquity and frequently high concentrations creates environmental concern regarding ecotoxicological effects. Although a wealth of literature addresses these as important environmental pollutants, there is a weak link between chemical investigations and biological effect assessments using ecotoxicological methods. Often, time consuming chemical methods do not provide the response needed for rapid environmental assessments. However, immunoassay techniques have been directed towards measuring environmental contaminants.1-10 The most common format used for 775 Fillmann et al. Vol. 18, No. 4, 2007 environmental analyses is the ELISA (enzyme-linked immunosorbent ...

Investigating the Quantitative Structure-Activity Relationships for Antibody Recognition of Two Immunoassays for Polycyclic Aromatic Hydrocarbons by Multiple Regression Methods

“…It should be pointed out that the RaPID PAHs ELISA kit is applied not only for water samples [ 9 , 10 ], but more often for soil samples [ 11 , 14 , 15 ]. In the pretreatment procedure, PAHs were usually extracted from the soil samples by methanol and diluted by buffer.…”

Future Trends for In Situ Monitoring of Polycyclic Aromatic Hydrocarbons in Water Sources: The Role of Immunosensing Techniques

“…Some of them target PAH detection by their physical characteristics (size, weight, etc.). For instance, BTEX RaPID Assay ® is a rapid field or laboratory enzyme immunoassay (from JJS technical services) that is able to analyze small aliphatic PAHs and carcinogenic PAHs (>4 aromatic rings) [69].…”