| Abstract
| - The coupling of antibody-, receptor-, or enzyme-basedinhibition assays postcolumn to chromatographic systemsprovides biological detectors with extraordinary highsensitivity and specificity. Three monoclonal antibodies(MC10E7, AD4G2, M8H5) directed against microcystinsand protein phosphatase 1 (PP1) were used as off-linedetectors for the HPLC separation of microcystins andnodularin in comparison to UV detection. For HPLC/ELISA coupling using antibody MC10E7, a detection limitof 0.04 ng microcystin-LR was achieved. The provisionalguideline value for microcystin-LR (1 μg/L, WHO) couldbe monitored without prior sample concentration, incontrast to UV detection. Quantification of microcystin-LR and two cross-reactants was demonstrated. Furthermore, cross-reactivity or enzyme inhibition of new microcystins, only available in small amounts, can be determinedby this method. Using a cyanobacterial extract, HPLC/ELISA coupling was compared to HPLC/UV and electrospray ionization mass spectrometry (ESI-TOFMS).
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