title: A new method for determination of plasma homocystine by isotope dilution and electrospray tandem mass spectrometry.
abstract: A new analytical determination method of homocystine in human plasma has been developed. The method utilises liquid chromatography coupled to ionspray tandem mass spectrometry. Quantitative analysis was achieved using as an internal standard homocystine-d8. Mass spectrometer operated in the multiple reaction mode: homocystine and homocystine-d8 were detected through the transition from the precursor to the product ion (from m/z 269.3 to 90.0, and m/z 277.3 to 94.0, respectively). The method is extremely sensitive, with limit of detection in the range of 6 fmol/L. The interassay and intraassay coefficients of variation for homocystine were 6.22% and 3.4%, respectively. The accuracy for the added homocystine ranged from 85% to 110%. High specificity of tandem mass spectrometry coupled with a fast chromatographic process is suitable for a rapid and reliable assay of homocystine.
authors.affiliation: Atherosclerosis and Thrombosis Unit, IRCCS Casa Sollievo della Sofferenza, S. Giovanni R. (FG), Italy.
authors.forename: Michela
authors.initials: M
authors.lastname: Tomaiuolo
authors.forename: Gennaro
authors.initials: G
authors.lastname: Vecchione
authors.forename: Elvira
authors.initials: E
authors.lastname: Grandone
authors.forename: Nicola
authors.initials: N
authors.lastname: Cocomazzi
authors.forename: Bruno
authors.initials: B
authors.lastname: Casetta
authors.forename: Giovanni
authors.initials: G
authors.lastname: Di Minno
authors.forename: Maurizio
authors.initials: M
authors.lastname: Margaglione
mesh_terms: D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D006711:Homocystine / Q000097:blood*; D006801:Humans; D007554:Isotopes; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods*
chemical_list: D007554:Isotopes; D006711:Homocystine