Article ID Journal Published Year Pages File Type
1246445 Talanta 2006 11 Pages PDF
Abstract

Polyclonal antibodies against microcystin-LR (MC-LR), a cyclic heptapeptide toxin, were generated in rabbits using MC-LR-BSA. An enzyme-linked immunosorbent assay (ELISA) was developed for the characterization of the antibodies and their potential use for analytical purposes. The concentration of MC-LR that inhibits 50% of antibody–antigen binding (IC50) was 0.5 μg L−1 for the indirect ELISA format and 0.9 μg L−1 for the direct ELISA, using MC-LR-horseradish peroxidase conjugate. The limit of detection corresponding to IC80 was found to be 0.06 μg L−1, well below the Word Health Organization level for drinking water of 1 μg L−1. The direct competitive ELISA was applied to water samples and was shown useful for screening purposes. The developed anti-microcystin antibodies were immobilized on solid supports for use in selective solid phase extraction (SPE) systems, prior to liquid chromatography (LC) quantification. An immunoaffinity cartridge (IAC), a Sepharose®-based cartridge incorporating 2 mg of antibodies allowed the selective and quantitative recovery of a mixture of 0.2 μg of MCs showing potential use in sample preparation of real matrices. When applied to water and green algae samples, average recoveries from Sepharose®-based cartridges were in the range of 86–113% for water samples and 85–92% for blue-green algae samples. Selectivity of the IAC clean-up was proven by comparison with non-specific solid phase extraction using octadecylsilica (ODS) sorbent. Results obtained using LC/UV after IAC clean-up agreed well with results obtained using liquid chromatography and mass spectrometry detection (LC/MS and LC/MS/MS) after SPE-C18 clean-up, allowing therefore to validate the resulting technique.

Related Topics
Physical Sciences and Engineering Chemistry Analytical Chemistry
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