title: Iron protoporphyrin-modified monolithic support for on-line preconcentration of angiotensin prior to CE analysis.
abstract: An on-line preconcentration method using a polymeric monolithic support is proposed for the retention of the decapeptide angiotensin I and its subsequent analysis by CZE. Monolithic capillary columns were prepared in fused-silica (FS) capillaries of 150 microm id by ionizing radiation-initiated in situ polymerization and cross-linking of diethylene glycol dimethacrylate and glycidyl methacrylate, and chemically modified with iron protoporphyrin IX (Fe-ProP). Monolithic microcolumns (8 mm long) were coupled on-line to the inlet of the separation capillary (FS capillary, 75 microm id x10 cm from the inlet to the microcolumn and 27 cm from the microcolumn to the detector). Angiotensin I was released from the sorbent by a 50 mM sodium phosphate, pH 2.5/ACN, 75:25 v/v solution and then analyzed by CZE with UV absorption detection at 214 nm. The concentration LOQ (CLOQ) was 0.5 ng/mL. The Fe-ProP-derivatized monolithic microcolumn coupled to the separation capillary exhibited a high retention capacity for peptide angiotensin I, and showed as much as 10,000-fold improvement in concentration sensitivity.
authors.affiliation: Department of Analytical Chemistry and Physicochemistry, Faculty of Pharmacy and Biochemistry, University of Buenos Aires, Ciudad de Buenos Aires, Argentina.
authors.forename: Angel
authors.initials: A
authors.lastname: Yone
authors.forename: María Lucía
authors.initials: ML
authors.lastname: Rusell
authors.forename: Mariano
authors.initials: M
authors.lastname: Grasselli
authors.forename: Nora M
authors.initials: NM
authors.lastname: Vizioli
mesh_terms: D000803:Angiotensin I / Q000302:isolation & purification*; D019075:Electrophoresis, Capillary / Q000295:instrumentation*; D008689:Methacrylates; D011524:Protoporphyrins / Q000737:chemistry*; D012822:Silicon Dioxide
chemical_list: D008689:Methacrylates; D011524:Protoporphyrins; C448299:iron protoporphyrin IX; C508263:poly(diethylene glycol dimethacrylate-co-glycidyl methacrylate); D012822:Silicon Dioxide; D000803:Angiotensin I