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Immunochemical and chromatographic methods for two anthropogenic markers of contamination in surface waters: caffeine and coprostanol

  • Caffeine (1,3,7-trimethylxanthine) and coprostanol (5β-cholestan-3β-ol) were detected in samples of Berlin's surface water. Their concentrations correlated with the contamination status of the samples, suggesting their usefulness as markers of human activity. Remarkably, caffeine concentrations were always well above the limit of quantitation of 0.025 µg/L. In order to screen surface water samples in larger series, the development of two novel methods was required: a monoclonal antibody-based immunoassay for caffeine and a dispersive liquid-liquid microextraction (DLLME) method, followed by liquid chromatography tandem mass spectrometry (LC-MS/MS) for coprostanol. The caffeine immunoassay developed shows the best analytical limit of detection (LOD) obtained so far for caffeine (0.001 µg/L), allows high-throughput analysis, and does not require sample pre-treatment. The assay was also successfully employed to measure caffeine in beverages, shampoos, caffeine tab-lets, and humanCaffeine (1,3,7-trimethylxanthine) and coprostanol (5β-cholestan-3β-ol) were detected in samples of Berlin's surface water. Their concentrations correlated with the contamination status of the samples, suggesting their usefulness as markers of human activity. Remarkably, caffeine concentrations were always well above the limit of quantitation of 0.025 µg/L. In order to screen surface water samples in larger series, the development of two novel methods was required: a monoclonal antibody-based immunoassay for caffeine and a dispersive liquid-liquid microextraction (DLLME) method, followed by liquid chromatography tandem mass spectrometry (LC-MS/MS) for coprostanol. The caffeine immunoassay developed shows the best analytical limit of detection (LOD) obtained so far for caffeine (0.001 µg/L), allows high-throughput analysis, and does not require sample pre-treatment. The assay was also successfully employed to measure caffeine in beverages, shampoos, caffeine tab-lets, and human saliva. Antibodies to coprostanol are not commercially available. A new strategy to generate anti-coprostanol antibodies was elaborated using an analogous com-pound as hapten – isolithocholic acid (ILA) – and immunizing a group of mice. A polyclonal anti-ILA serum was produced, which binds coprostanol but the low affinity did not permit setting up an immunoassay to measure environmental concentrations of the analyte (in the range of ng/L). Specific anti-ILA immunoglobulin G were also found in the faeces of the immunized mice. Coprostanol was quantified in the water samples using a newly developed LC-MS/MS method using atmospheric pressure chemical ionisation (APCI). Concentrations above 0.1 µg/L were determined after sample preconcentration using DLLME. This extraction method also proved to be successful for enrichment of coprostanol-related compounds such as cholesterol, cholestanol, cholestanone, ergosterol, and stigmasterol.zeige mehrzeige weniger

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Metadaten
Autor*innen:José Joao Carvalho
Dokumenttyp:Dissertation
Veröffentlichungsform:Graue Literatur
Sprache:Englisch
Jahr der Erstveröffentlichung:2011
Herausgeber (Institution):Humboldt-Universität zu Berlin
Titel verleihende Institution:Humboldt-Universität zu Berlin, Mathematisch-Naturwissenschaftliche Fakultät I
Verlagsort:Berlin
Erste Seite:1
Letzte Seite:280
Freie Schlagwörter:Coprostanol; ELISA; Hybridoma-Technik; Immunoassay; Koffein; LC-MS/MS; Marker; Umweltanalytik
DOI:10.18452/16420
Verfügbarkeit des Dokuments:Datei im Netzwerk der BAM verfügbar ("Closed Access")
Datum der Freischaltung:19.02.2016
Jahr der Fertigstellung:2011
Referierte Publikation:Nein
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