title: High-performance liquid chromatography-ionspray mass spectrometry for the specific determination of digoxin and some related cardiac glycosides in human plasma.
abstract: An original method based upon high-performance liquid chromatography coupled to ionspray mass spectrometry (HPLC-ISP-MS) has been developed for the identification and quantification in plasma of several cardiac glycosides, namely digoxin, digitoxin, lanatoside C and acetyldigitoxin. After single-step liquid-liquid extraction by chloroform-2-propanol (95:5, v/v) at pH 9.5 using oleandrin as an internal standard, solutes are separated on a 4 microm NovaPak C18 (Waters) column (150x2.0 mm, I.D.), using a gradient of acetonitrile-2 mM NH4COOH, pH 3 buffer (flow-rate 200 microl/min, post-column split 1:3). Detection is done by a Perkin-Elmer Sciex API-100 mass analyzer equipped with an ISP interface. In most instances the major ion observed is not [M+H]+ as expected, but [M+NH4]+. The mean retention times (min) are: lanatoside C, 5.74; digoxin, 6.00; digitoxin, 8.08, oleandrin, 8.30, acetyldigitoxin, 8.66 and 9.01 (isomers alpha and beta, respectively). The lower limits of detection in single ion monitoring mode range from 0.15 ng/ml (alpha- and beta-acetyldigitoxin) to 0.60 ng/ml (lanatoside C), making the method less sensitive than radioimmunoassay, whereas it is much more specific.
authors.affiliation: Institut de Médecine Légale, Strasbourg, France.
authors.forename: A
authors.initials: A
authors.lastname: Tracqui
authors.forename: P
authors.initials: P
authors.lastname: Kintz
authors.forename: B
authors.initials: B
authors.lastname: Ludes
authors.forename: P
authors.initials: P
authors.lastname: Mangin
mesh_terms: D000112:Acetyldigitoxins / Q000097:blood; D002301:Cardiac Glycosides / Q000097:blood*; D002316:Cardiotonic Agents / Q000097:blood*; D002851:Chromatography, High Pressure Liquid; D004074:Digitoxin / Q000097:blood; D004077:Digoxin / Q000097:blood*; D008401:Gas Chromatography-Mass Spectrometry; D006801:Humans; D007799:Lanatosides / Q000097:blood; D010042:Ouabain / Q000097:blood; D012680:Sensitivity and Specificity
chemical_list: D000112:Acetyldigitoxins; D002301:Cardiac Glycosides; D002316:Cardiotonic Agents; D007799:Lanatosides; D010042:Ouabain; C018548:lanatoside C; D004077:Digoxin; D004074:Digitoxin