Iron protoporphyrin-modified monolithic support for on-line preconcentration of angiotensin prior to CE analysis

ANGEL YONE; M LUCIA RUSSEL; MARIANO GRASSELLI; NORA M. VIZIOLI

ELECTROPHORESIS

Wiley-VCH Verlag

Año: 2007 vol. 28 p. 2216 - 2218

0173-0835

An online preconcentration method using a polymeric monolithic support is proposed for the retention of decapeptide angiotensin I and its subsequent separation by capillary zone electrophoresis (CZE). Monolithic capillary columns were prepared in fused-silica (FS) capillaries of 150 ìm inner diameter (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 were coupled online at the inlet of the separation capillary (FS capillary, 75 ìm ID x from the inlet to the microextractor and from microextractor to detector). Angiotensin I was released from the sorbent by a 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 limit of quantification (CLOQ) was 0.5 ng/mL. The Fe-ProP-derivatized monolithic microextractor coupled to the separation capillary exhibited a high retention capacity for peptide angiotensin I and showed as much as 10000-fold improvement in concentration sensitivity.