title: Determination of linsidomine in human plasma by tandem LC-MS with ESI.
abstract: A sensitive method for the determination of linsidomine in plasma was developed, using high-performance liquid chromatographic (HPLC) separation with tandem mass spectrometric detection. Linsidomine was derivatised with propyl chloroformate and extracted with tert-butyl methyl ether/1,2-dichloroethane (55:45, v/v), back-extracted into HCl (0.01 M) followed by alkalinisation and back-extraction into ether; the final ether extract evaporated, reconstituted in mobile phase and then separated on a Phenomenex Luna C18 (2) 5 micron 2.1 x 150 mm column with a mobile phase consisting of methanol water formic acid (98/100%) (400:600:0.05, v/v/v) at a flow-rate of 0.4 ml min(-1). Detection was achieved by a Finnigan MAT mass spectrometer (LCQ) at unit resolution in the selected reaction monitoring (SRM) mode monitoring the transition of the protonated molecular ion m/z 257.0 to the product ion m/z 86.0. The mean recovery for linsidomine was 51% with a lower limit of quantification of 0.70 ng/ml using 1 ml plasma for extraction. This LC-MS/MS method for the determination of linsidomine in human plasma allows for better specificity and a higher sample throughput than the traditional LC-UV methods. It also demonstrates the profound effect that the composition of acidic modifiers and matrix constituents can have on the electrospray ionisation (ESI) of the analyte.
authors.affiliation: Department of Pharmacology, FARMOVS Research Centre for Clinical Pharmacology and Drug Development, University of the Orange Free State, Bloemfontein, South Africa. gnfmfcws@frm.uovs.ac.za
authors.forename: F C
authors.initials: FC
authors.lastname: Sutherland
authors.forename: A D
authors.initials: AD
authors.lastname: de Jager
authors.forename: K J
authors.initials: KJ
authors.lastname: Swart
authors.forename: H K
authors.initials: HK
authors.lastname: Hundt
authors.forename: T
authors.initials: T
authors.lastname: Scanes
authors.forename: A F
authors.initials: AF
authors.lastname: Hundt
mesh_terms: D002853:Chromatography, Liquid / Q000379:methods*; D006801:Humans; D007474:Ion Exchange; D013058:Mass Spectrometry / Q000379:methods*; D008981:Molsidomine / Q000031:analogs & derivatives* / Q000097:blood; D011786:Quality Control; D015203:Reproducibility of Results; D014665:Vasodilator Agents / Q000097:blood*
chemical_list: D014665:Vasodilator Agents; C002385:linsidomine; D008981:Molsidomine