Quantification of [Dmt1]DALDA in ovine plasma by on-line liquid chromatography/quadrupole time-of-flight mass spectrometry

• Published in: Rapid communications in mass spectrometry 2003-01, Vol.17 (6), p.538-546
• Main Authors: Wan, Haibao, Desiderio, Dominic M.
• Format: Article
• Language: English
• Subjects: Amino Acid Sequence; Animals; Calibration; Chromatography, Liquid - methods; Electrochemistry; Ions; Mass Spectrometry - methods; Molecular Structure; Oligopeptides - blood; Oligopeptides - chemical synthesis; Oligopeptides - chemistry; Receptors, Opioid, mu - agonists; Reference Standards; Sensitivity and Specificity; Sheep - blood
• ISSN: 0951-4198; 1097-0231
• DOI: 10.1002/rcm.948

The synthetic peptide [Dmt1]DALDA (Dmt‐D‐Arg‐Phe‐Lys‐NH2; Dmt = 2′,6′‐dimethyltyrosine; ‘super‐DALDA’) is a mu opioid‐receptor agonist. On‐line liquid chromatography/quadrupole time‐of‐flight mass spectrometry and the corresponding stable isotope‐incorporated synthetic peptide internal standard were used to quantify [Dmt1]DALDA that had been extracted from ovine plasma samples. The [M+2H]2+ ion was used to construct the calibration curve, and the product ion was used for verification of the peptide. The detection sensitivity for the [Dmt1]DALDA [M+2H]2+ ion was 12.5 fmol and 50 fmol for the m/z 432.3 product ion. The concentration profile of [Dmt1]DALDA was determined from a set of ovine plasma samples. The molecular specificity of the peptide quantification was confirmed by tandem mass spectrometry (MS/MS). Copyright © 2003 John Wiley & Sons, Ltd.