title: Quantitative analysis of [Dmt(1)]DALDA in ovine plasma by capillary liquid chromatography-nanospray ion-trap mass spectrometry.
abstract: The synthetic opioid peptide analog Dmt-D-Arg-Phe-Lys-NH(2) ([Dmt(1)]DALDA; [Dmt= 2',6'-dimethyltyrosine) is a highly potent and selective mu opioid-receptor agonist. A very sensitive and robust capillary liquid chromatography/nanospray ion-trap (IT) mass spectrometry method has been developed to quantify [Dmt(1)]DALDA in ovine plasma, using deuterated [Dmt(1)]DALDA as the internal standard. The standard MS/MS spectra of d(0)- and d(5)-[Dmt(1)]DALDA were obtained, and the collision energy was experimentally optimized to 25%. The product ion [ M + 2H-NH(3)](2+) (m/z 312.2) was used to identify and to quantify the synthetic opioid peptide analog in ovine plasma samples. The MS/MS detection sensitivity for [Dmt(1)]DALDA was 625 amol. A calibration curve was constructed, and quantitative analysis was performed on a series of ovine plasma samples.
authors.affiliation: Charles B Stout Neuroscience Mass Spectrometry Laboratory, University of Tennessee Health Science Center, 847 Monroe Avenue, Memphis, TN 38163, USA.
authors.forename: Haibao
authors.initials: H
authors.lastname: Wan
authors.forename: Edward S
authors.initials: ES
authors.lastname: Umstot
authors.forename: Hazel H
authors.initials: HH
authors.lastname: Szeto
authors.forename: Peter W
authors.initials: PW
authors.lastname: Schiller
authors.forename: Dominic M
authors.initials: DM
authors.lastname: Desiderio
mesh_terms: D000818:Animals; D002853:Chromatography, Liquid / Q000379:methods*; D013058:Mass Spectrometry / Q000379:methods*; D036103:Nanotechnology; D009842:Oligopeptides / Q000097:blood*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D012756:Sheep
chemical_list: C424424:2',6'-dimethyltyrosyl-arginyl-phenylalanyl-lysinamide; D009842:Oligopeptides