title: Study of immobilized metal affinity chromatography sorbents for the analysis of peptides by on-line solid-phase extraction capillary electrophoresis-mass spectrometry.
abstract: Several commercial immobilized metal affinity chromatography sorbents were evaluated in this study for the analysis of two small peptide fragments of the amyloid β-protein (Aβ) (Aβ(1-15) and Aβ(10-20) peptides) by on-line immobilized metal affinity SPE-CE (IMA-SPE-CE). The performance of a nickel metal ion (Ni(II)) sorbent based on nitrilotriacetic acid as a chelating agent was significantly better than two copper metal ion (Cu(II)) sorbents based on iminodiacetic acid. A BGE of 25 mM phosphate (pH 7.4) and an eluent of 50 mM imidazole (in BGE) yielded a 25-fold and 5-fold decrease in the LODs by IMA-SPE-CE-UV for Aβ(1-15) and Aβ(10-20) peptides (0.1 and 0.5 μg/mL, respectively) with regard to CE-UV (2.5 μg/mL for both peptides). The phosphate BGE was also used in IMA-SPE-CE-MS, but the eluent needed to be substituted by a 0.5% HAc v/v solution. Under optimum preconcentration and detection conditions, reproducibility of peak areas and migration times was acceptable (23.2 and 12.0%RSD, respectively). The method was more sensitive for Aβ(10-20) peptide, which could be detected until 0.25 μg/mL. Linearity for Aβ(10-20) peptide was good in a narrow concentration range (0.25-2.5 μg/mL, R(2) = 0.93). Lastly, the potential of the optimized Ni(II)-IMA-SPE-CE-MS method for the analysis of amyloid peptides in biological fluids was evaluated by analyzing spiked plasma and serum samples.
authors: Department of Analytical Chemistry, University of Barcelona, Barcelona, Spain.
authors: Lorena
authors: L
authors: Ortiz-Martin
authors: Fernando
authors: F
authors: Benavente
authors: Silvia
authors: S
authors: Medina-Casanellas
authors: Estela
authors: E
authors: Giménez
authors: Victoria
authors: V
authors: Sanz-Nebot
mesh_terms: D016229:Amyloid beta-Peptides / Q000097:blood* / Q000737:chemistry; D002614:Chelating Agents; D002846:Chromatography, Affinity; D019075:Electrophoresis, Capillary / Q000379:methods*; D006801:Humans; D013058:Mass Spectrometry / Q000379:methods*; D009532:Nickel / Q000737:chemistry; D052616:Solid Phase Extraction / Q000379:methods*
chemical_list: D016229:Amyloid beta-Peptides; D002614:Chelating Agents; D009532:Nickel
keywords: Amyloid peptide; Capillary electrophoresis; Mass spectrometry; Metal affinity; On-line preconcentration