title: Fluorescence detection of cardenolides in reversed-phase high-performance liquid chromatography after post-column derivatization.
abstract: Methods for the fluorescence derivatization of cardiac glycosides with concentrated acids from TLC are adopted to HPLC for post-column derivatization. The column effluent is blended with concentrated acids in a knitted tube reactor, which enables derivatization with negligible increase in chromatographic peak width. The selectivity of the reaction is temperature-dependent and influenced by the respective acid. Reactivity increases from H3PO4-->CH3SO3H[symbol: see text]H2SO4. The conversion of digoxigenin, digitoxigenin and their digitoxosides is accelerated by Cu(II) acetate or Co(II) nitrate in H2SO4. Combined with a new two-mode, single-column solid-phase sample preparation, cardiac glycoside levels of less than 100 pg/glycoside in 1 ml plasma are detectable.
authors.affiliation: Institute of Pharmacology of Natural Compounds, University of Ulm, Germany.
authors.forename: K
authors.initials: K
authors.lastname: Belsner
authors.forename: B
authors.initials: B
authors.lastname: Büchele
mesh_terms: D000143:Acids / Q000737:chemistry; D000368:Aged; D002298:Cardenolides / Q000097:blood* / Q000737:chemistry / Q000493:pharmacokinetics; D002316:Cardiotonic Agents / Q000097:blood* / Q000737:chemistry / Q000493:pharmacokinetics; D002851:Chromatography, High Pressure Liquid; D003300:Copper / Q000737:chemistry; D004076:Digoxigenin / Q000032:analysis / Q000737:chemistry; D004077:Digoxin / Q000097:blood* / Q000737:chemistry / Q000493:pharmacokinetics; D005453:Fluorescence; D006801:Humans; D008297:Male; D008670:Metals / Q000737:chemistry; D008875:Middle Aged; D009942:Organometallic Compounds / Q000737:chemistry; D013050:Spectrometry, Fluorescence; D013256:Steroids / Q000737:chemistry; D013696:Temperature
chemical_list: D000143:Acids; D002298:Cardenolides; D002316:Cardiotonic Agents; D008670:Metals; D009942:Organometallic Compounds; D013256:Steroids; C015092:cupric acetate; D004077:Digoxin; D003300:Copper; D004076:Digoxigenin