title: Simultaneous determination of cross-reactive leukotrienes in biological matrices using on-line liquid chromatography immunochemical detection.
abstract: Sulfidopeptide leukotrienes, which are important biomarkers for several diseases, are commonly measured by microtiter plate immunoassays. These immunoassays, however, cannot distinguish between several structurally similar leukotrienes and their cross-reactive metabolites and, therefore, need extensive sample handling and fractionation by means of liquid chromatography (LC). This paper describes the development and automation of a continuous-flow immunochemical detection (ICD) system and its subsequent on-line coupling to LC. The on-line LC-ICD system based on fluorescence-labeled leukotriene E4 (LTE4) was used to determine sulfidopeptide leukotrienes and their cross-reactive metabolites in a single run. Furthermore, biological matrices, e.g., urine and human cell extracts, were analyzed, the only sample pretreatment being on-line solid-phase extraction (SPE) on a novel RP-C4 restricted-access support. The determination limit of LTE4 in urine was 0.2 ng/mL (800 fmol; injection volume, 2000 microL; signal-to-noise ratio, 10). The system was linear from 0.2 to 1.0 ng/mL LTE4. Using nonlinear curve-fitting, the range could be expanded to 2.5 ng/mL. It is shown that, besides quantitation of known analytes, on-line LC-ICD is useful in the discovery of cross-reactive LTE4 metabolites.
authors.affiliation: Leiden/Amsterdam Center for Drug Research, Division of Analytical Chemistry, Leiden University, The Netherlands.
authors.forename: A J
authors.initials: AJ
authors.lastname: Oosterkamp
authors.forename: H
authors.initials: H
authors.lastname: Irth
authors.forename: L
authors.initials: L
authors.lastname: Heintz
authors.forename: G
authors.initials: G
authors.lastname: Marko-Varga
authors.forename: U R
authors.initials: UR
authors.lastname: Tjaden
authors.forename: J
authors.initials: J
authors.lastname: van der Greef
mesh_terms: D000937:Antigen-Antibody Reactions; D002457:Cell Extracts; D002853:Chromatography, Liquid / Q000379:methods*; D003429:Cross Reactions; D005455:Fluorescent Antibody Technique; D006801:Humans; D015289:Leukotrienes / Q000032:analysis* / Q000276:immunology / Q000652:urine
chemical_list: D002457:Cell Extracts; D015289:Leukotrienes