Analysis of Peptides in Plasma by High Performance Liquid Chromatography Coupled with Electrospray Ionization Mass Spectrometry

In this study, a high performance liquid chromatography coupled with electrospray ionization mass spectrometry (HPLC-ESI-MS) method for the determination of eight endogenous peptides, which included angiotensin-II, neurotensin, 5-met-enkephalin, 5-leu-enkephalin, somatostatin, bradykinin, dynorphin A and oxidized glutathione, was developed. MS parameters were optimized in order to obtain the best signal intensity. The optimum MS parameters were: fragmentor: 100 V; nebulizer gas (N2) pressure: 40 psi; drying gas (N2) flow rate: 10 L/min; drying gas temperature: 350 °C; capillary voltage: 2000 V. Validation of the method showed positive results. The correlation coefficients (R2) between the peak areas and the corresponding concentrations of peptides were greater than 0.9903. The limits of detection (LODs) (S/N = 3) of the eight peptides were 3.88 ng/mL ~ 17.5 ng/mL. The developed method had been successfully applied to analyzing the human plasma fortified with the eight peptides, which indicated the potential of the methodology for the analysis of biological sample.