title: Preparation and evaluation of open tubular C18-silica monolithic microcartridges for preconcentration of peptides by on-line solid phase extraction capillary electrophoresis.
abstract: In this study, C18-silica monoliths were synthesized as a porous layer in open tubular capillary columns, to be cut later into microcartridges for the analysis of neuropeptides by on-line solid-phase extraction capillary electrophoresis with UV and MS detection (SPE-CE-UV and SPE-CE-MS). First, several types of C18-silica monolithic (MtC18) microcartridges were used to analyse standard solutions of five neuropeptides (i.e. dynorphin A (1-7), substance P (7-11), endomorphin 1, methionine enkephalin and [Ala]-methionine enkephalin). The MtC18 sorbents were especially selective against endomorphin 1 and substance P (7-11)). The best results in terms of sensitivity and inter-microcartridge reproducibility were achieved with the microcartridges obtained from a 10-cm open tubular capillary column with a thin monolithic coating with large through-pores (1-5μm). Run-to-run repeatability, microcartridge durability, linearity ranges and LODs were studied by MtC18-SPE-CE-MS. As expected due to their greater selectivity, the best LOD enhancement was obtained for End1 and SP (7-11) (50 times with regard to CE-MS). Finally, the suitability of the methodology for analysing biological fluids was tested with plasma samples spiked with End1 and SP (7-11). Results obtained were promising because both neuropeptides could be detected at 0.05μgmL(-1), which was almost the same concentration level as for the standard solutions (0.01μgmL(-1)).
authors.affiliation: Department of Analytical Chemistry, University of Barcelona, Diagonal 645, 08028 Barcelona, Spain.
authors.forename: Elena
authors.initials: E
authors.lastname: Ortiz-Villanueva
authors.affiliation: Department of Analytical Chemistry, University of Barcelona, Diagonal 645, 08028 Barcelona, Spain. Electronic address: fbenavente@ub.edu.
authors.forename: Fernando
authors.initials: F
authors.lastname: Benavente
authors.affiliation: Department of Analytical Chemistry, University of Barcelona, Diagonal 645, 08028 Barcelona, Spain.
authors.forename: Estela
authors.initials: E
authors.lastname: Giménez
authors.affiliation: Department of Chemical Technology, Abant Izzet Baysal University, 14900 Bolu, Turkey.
authors.forename: Fatma
authors.initials: F
authors.lastname: Yilmaz
authors.affiliation: Department of Analytical Chemistry, University of Barcelona, Diagonal 645, 08028 Barcelona, Spain.
authors.forename: Victoria
authors.initials: V
authors.lastname: Sanz-Nebot
mesh_terms: D000595:Amino Acid Sequence; D019075:Electrophoresis, Capillary / Q000379:methods*; D057230:Limit of Detection; D013058:Mass Spectrometry / Q000379:methods; D008969:Molecular Sequence Data; D009842:Oligopeptides / Q000032:analysis / Q000302:isolation & purification*; D010446:Peptide Fragments / Q000032:analysis / Q000302:isolation & purification*; D012822:Silicon Dioxide / Q000737:chemistry*; D052616:Solid Phase Extraction / Q000379:methods*; D013373:Substance P / Q000032:analysis / Q000302:isolation & purification*
chemical_list: D009842:Oligopeptides; D010446:Peptide Fragments; C105293:endomorphin 1; D013373:Substance P; C061335:substance P (7-11); D012822:Silicon Dioxide
keywords: Mass spectrometry; Neuropeptides; On-line preconcentration; Open tubular column; Silica monolith