| Abstract
| - ELISA methods have been developed for screening contamination of water resources by linear alkyl benzenesulfonates (LAS) or the most immediate degradationproducts, the long chain sulfophenyl carboxylates, SPCs.The assay uses antibodies raised through pseudoheterologous immunization strategies using an equimolarmixture of two immunogens (SFA−KLH and 13C13-SPC−KLH) prepared by coupling N-(4-alkylphenyl)sulfonyl-3-aminopropanoic acid (SFA) and p-(1-carboxy-13-tridecyl)phenylsulfonic acid (13C13-SPC) to keyhole limpet hemocyanin (KLH). The immunizing haptens have been designed to address recognition versus two different epitopesof the molecule. The SFA hapten maximizes recognitionof the alkyl moiety while preserving the complexity of thedifferent alkyl chains present in the LAS technical mixture.The 13C13-SPC hapten addresses recognition of thecommon and highly antigenic phenylsulfonic group. Theantisera raised using this strategy have been shown to besuperior to those obtained through homologous immunization procedures using a single substance. By usingan indirect ELISA format, LAS and long-chain SPCs canbe detected down to 1.8 and 0.2 μg L-1, respectively.Coefficients of variation of 6 and 12% within and betweenassays, respectively, demonstrate immunoassay reproducibility. The assay can be used in media with a widerange of pH and ionic strength values. Preliminary experiments performed to assess matrix effects have demonstrated the potential applicability of the method as ascreening tool to assess contamination by these types ofsurfactants in natural water samples.
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