On-Line Solid-Phase Extraction Capillary Electrophoresis Mass Spectrometry for Preconcentration and Clean-Up of Peptides and Proteins.

One of the major drawbacks of capillary electrophoresis (CE) and other microscale separation techniques, for the analysis of low abundant peptides and proteins in complex samples, are the poor concentration limits of detection. Several strategies have been developed to improve CE sensitivity. Here, we describe an on-line solid-phase extraction capillary electrophoresis mass spectrometry method with a commercial C18 sorbent for clean-up and preconcentration of neuropeptides from highly diluted biological samples.

Study of immobilized metal affinity chromatography sorbents for the analysis of peptides by on-line solid-phase extraction capillary electrophoresis-mass spectrometry.

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.

Evaluation of fritless solid-phase extraction coupled on-line with capillary electrophoresis-mass spectrometry for the analysis of opioid peptides in cerebrospinal fluid.

Fritless SPE on-line coupled to CE with UV and MS detection (SPE-CE-UV and SPE-CE-MS) was evaluated for the analysis of opioid peptides. A microcartridge of 150 μm id was packed with a C18 sorbent (particle size > 50 μm), which was retained between a short inlet capillary and a separation capillary (50 μm id). Several experimental parameters were optimized by SPE-CE-UV using solutions of dynorphin A (DynA), endomorphin 1 (End1), and methionine-enkephaline (Met).

On-line immunoaffinity solid-phase extraction capillary electrophoresis mass spectrometry for the analysis of large biomolecules: a preliminary report.

The analysis of large biomolecules by on-line immunoaffinity solid-phase extraction capillary electrophoresis mass spectrometry (IA-SPE-CE-MS) remains unexplored because of the complex issues that need to be addressed. In this preliminary study, we used the human glycoprotein transferrin (Tf) as a model of a large biomolecule. First, we established by CE-UV a novel method compatible with IA-SPE-CE-MS, based on the use of a fused silica capillary coated with an anionic derivative of polyacrylamide (UltraTrol(TM) Dynamic Pre-Coat High Normal, HN) to prevent protein adsorption.

Low-picomolar analysis of peptides by on-line coupling of fritless solid-phase extraction to sheathless capillary electrophoresis-mass spectrometry.

A novel fritless solid-phase extraction (SPE) microcartridge was designed for combination with sheathless capillary electrophoresis-mass spectrometry (sheathless CE-MS) employing a prototype porous-tip capillary for nanoelectrospray ionization (nanoESI). The inlet of the separation capillary (30μm inner diameter (id), 150μm outer diameter (od)) was inserted in a 4mm long SPE microcartridge (150μm id, 365μm od) packed with a C18 sorbent of 55-105μm particle size. Performance of the SPE-CE-MS system was evaluated using diluted solutions of the three opioid peptides dynorphin A (1-7) (DynA), endomorphin 1 (End1) and met-enkephalin (Met).

Preparation and evaluation of an immunoaffinity sorbent with Fab' antibody fragments for the analysis of opioid peptides by on-line immunoaffinity solid-phase extraction capillary electrophoresis-mass spectrometry.

An immunoaffinity (IA) sorbent with antibody fragments was prepared for the analysis of opioid peptides by on-line immunoaffinity solid-phase extraction capillary electrophoresis-mass spectrometry (IA-SPE-CE-MS). The antibody fragmentation was evaluated by MALDI-TOF-MS. Fab' fragments obtained from a polyclonal IgG antibody against Endomorphins 1 and 2 (End1 and End2) were covalently attached to succinimidyl silica particles to prepare the IA sorbent.

Preparation and evaluation of an immunoaffinity sorbent for the analysis of opioid peptides by on-line immunoaffinity solid-phase extraction capillary electrophoresis-mass spectrometry.

In this study, we explored a procedure for the preparation of an immunoaffinity (IA) sorbent for the analysis of opioid peptides by on-line immunoaffinity solid-phase extraction capillary electrophoresis-mass spectrometry (IA-SPE-CE-MS). We followed a site-specific antibody immobilization approach based on the covalent attachment of the oxidized antibodies through their carbohydrate moieties to hydrazide silica particles, using a polyclonal antibody against Endomorphin 1 and 2 (End1 and End2). The main features of the IA sorbent were studied, such as the amount of hydrazide groups and antibodies attached onto oxidized diol silica particles.

Transient isotachophoresis in on-line solid phase extraction capillary electrophoresis time-of-flight-mass spectrometry for peptide analysis in human plasma.

In this study, we evaluated the combination of transient isotachophoresis with on-line solid-phase extraction capillary electrophoresis time-of-flight mass spectrometry (SPE-tITP-CE-TOF-MS) to improve sensitivity of peptide analysis, using several opioid peptides as model compounds. First, standard solutions were analyzed in order to establish the tITP-CE methodology using UV and TOF-MS detection. The volume and composition of the leading and terminating electrolytes (i.

Investigation of commercial sorbents for the analysis of opioid peptides in human plasma by on-line SPE-CE.

In this study, we investigated the performance of several commercial sorbents (Sep-pack) C18, (t)C18, C8 and (t)C2, Oasis HLB, Isolute ENV+, Strata-X and Oasis MCX) for the determination of opioid peptides by solid-phase extraction coupled on-line to capillary electrophoresis (SPE-CE). First, standard solutions were analyzed in order to achieve the lowest LOD and the best electrophoretic separations using UV detection. The best results were obtained using C18, C8 and (t)C2 sorbents, which were examined for the analysis of spiked human plasma samples.