title: Antibody-free ultra-high performance liquid chromatography/tandem mass spectrometry measurement of angiotensin I and II using magnetic epitope-imprinted polymers.
abstract: The major challenges in measuring plasma renin activity (PRA) stem from the complexity of biological matrix, as well as from the instability and low circulating concentration of angiotensin. In this study, an ultra-high performance liquid chromatography/tandem mass spectrometry (UPLC-MS/MS) based technique has been developed for the measurement of angiotensin using magnetically imprinted polymers for simultaneous enrichment of the precursor peptide angiotensin II (Ang II) and the upstream peptide precursor angiotensin I (Ang I). This technique involved surface graft imprinting in aqueous solutions using vinyl-modified nano-iron oxide as solid supports, the specificity determinant of Ang I and Ang II as the epitope, and methacrylic acid and N-t-butylacrylamide as functional monomers. The vinyl-modified nano-iron oxide acted as a magnetic separation media, and the molecularly imprinted shell provided analyte selectivity for the recognition of Ang I and Ang II. Selective enrichment of Ang I and Ang II was accomplished by the magnetically imprinted polymers, followed by a magnetic separation procedure and subsequent quantification by UPLC-MS/MS in the positive ionization mode with multiple reaction monitoring. Through the latter protocol, a low limit of detection could be realized, viz. 0.07ng/mL and 0.06ng/mL for Ang I and II, respectively, which was thoroughly validated for accuracy and reproducibility through analyzing Ang I and Ang II in human plasma samples.
authors.affiliation: MOE Key Laboratory of Laser Life Science, South China Normal University, Guangzhou 510006, China; Guangzhou Center for Disease Control and Prevention, Guangzhou 510440, China.
authors.forename: Lei
authors.initials: L
authors.lastname: Tan
authors.affiliation: MOE Key Laboratory of Laser Life Science, South China Normal University, Guangzhou 510006, China.
authors.forename: Zerong
authors.initials: Z
authors.lastname: Yu
authors.affiliation: MOE Key Laboratory of Laser Life Science, South China Normal University, Guangzhou 510006, China.
authors.forename: Xiaoming
authors.initials: X
authors.lastname: Zhou
authors.affiliation: MOE Key Laboratory of Laser Life Science, South China Normal University, Guangzhou 510006, China.
authors.forename: Da
authors.initials: D
authors.lastname: Xing
authors.affiliation: Guangzhou Center for Disease Control and Prevention, Guangzhou 510440, China.
authors.forename: Xiaoyan
authors.initials: X
authors.lastname: Luo
authors.affiliation: Guangzhou Center for Disease Control and Prevention, Guangzhou 510440, China.
authors.forename: Rongfei
authors.initials: R
authors.lastname: Peng
authors.affiliation: MOE Key Laboratory of Laser Life Science, South China Normal University, Guangzhou 510006, China. Electronic address: tanglab@scnu.edu.cn.
authors.forename: Youwen
authors.initials: Y
authors.lastname: Tang
mesh_terms: D000178:Acrylamides / Q000737:chemistry*; D000803:Angiotensin I / Q000032:analysis*; D000804:Angiotensin II / Q000032:analysis*; D002851:Chromatography, High Pressure Liquid / Q000379:methods; D002853:Chromatography, Liquid / Q000379:methods; D000939:Epitopes; D005240:Feasibility Studies; D006801:Humans; D058185:Magnetite Nanoparticles; D054802:Molecular Imprinting; D011109:Polymethacrylic Acids / Q000737:chemistry*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D053719:Tandem Mass Spectrometry / Q000379:methods
chemical_list: D000178:Acrylamides; D000939:Epitopes; D058185:Magnetite Nanoparticles; D011109:Polymethacrylic Acids; D000804:Angiotensin II; D000803:Angiotensin I; C115287:tert-butylacrylamide
keywords: Angiotensin; Epitope; Magnetic separation; Molecular imprinting; UPLC–MS/MS