Synthesis of sulfo/vinyl biphasic silica hybrid monolithic capillary column and its application to on-column preconcentration for capillary electrochromatography
State Key Laboratory of Chemo/Biosensing & Chemometrics, College of Chemistry & Chemical Engineering, Hunan University, Changsha 410082, China. Journal of Chromatography A
(Impact Factor: 4.17).
01/2012; 1233:91-9. DOI: 10.1016/j.chroma.2012.01.024
A novel method to synthesize sulfo/vinyl biphasic silica hybrid monolithic column in one step was developed for on-column preconcentration. In this method, sulfo-based segment is located at the inlet of capillary column, which acts as preconcentration column. It is synthesized by polymerization of 3-sulfopropyl methacrylate potassium salt (SPMA) and vinyltrimethoxysilane (VTMS) with tetramethoxysilane (TOMS). Close to the preconcentration column, a vinyl functionalized segment is formed and serves as separation column. It is synthesized by polymerization of only VTMS with TOMS. Vinyl groups on vinyl functionalized segment are modified with ligand containing sulfhydryl group, such as octadecanethiol (C(18)-SH for short), 6-mercapto-1-hexanol (HO-C(6)-SH for short), via thiol-ene click reaction. The interface between the two segments is seamless and without any dead volume. The applicability of this system is demonstrated by successful separation of closely related amines including p-phenylenediamine, aniline, p-toluidine, N-methyl aniline, N,N'-dimethylaniline, and diphenylamine. Good separation and enrichment are obtained. The proposed system is also successfully applied to complex biological samples, such as peptide, diluted BSA hydrolysate, and the results indicate that the system has a capability for preconcentration of low abundance peptides.
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- "CV <5% with n = 3 (Three repetitions for each point). of monomers (ODT). Moreover, an increase of the irradiation duration or of the monomer concentration (above 1 M) does not lead to any decrease in efficiency as previously observed by several authors  . Such loss of efficiency was observed in the case of pore clogging consecutive to the growth of thick polymeric layers in the photopolymerization process. "
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ABSTRACT: This paper presents a photografting process of monolithic silica capillary columns based on the ene-thiol click chemistry. This study is performed on a "generic" vinyl-functionalized silica monolith (Hmin 6±1μm). The photoclick reaction is investigated using different thiol monomers (octadecanethiol, cysteine and sodium mercaptoethanesulfonate) to prepare capillary columns dedicated to various chromatographic modes (reversed-phase, HILIC and strong cation exchange). Whatever the monomer used, the photografting reaction is achieved in less than 5min with a relatively high thiol monomer content. This allows preparing highly retentive and efficient monolithic columns while avoiding polymerization and/or column clogging. In addition to the aforementioned properties (duration, versatility, efficiency), this photo-triggered chemical reaction allows addressing several appropriate surface functionalizations inside a single monolithic column in order to prepare nanovolume multimodal capillary columns. A multimodal biphasic monolithic column with a 1cm length cation-exchange segment followed by a 9cm length reversed-phase segment (SCX-RP) is prepared through two successive photografting reactions using a UV-mask to localize the reactions. This multimodal biphasic column is investigated using a model sample for the selective fractionation and separation of cationic and neutral compounds and is applied to the on-line preconcentration and separation of β-blockers.
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ABSTRACT: Since "omics" techniques emerged, plant studies, from biochemistry to ecology, have become more comprehensive. Plant proteomics and metabolomics enable the construction of databases that, with the help of genomics and informatics, show the data obtained as a system. Thus, all the constituents of the system can be seen with their interactions in both space and time. For instance, perturbations in a plant ecosystem as a consequence of application of herbicides or exposure to pollutants can be predicted by using information gathered from these databases. Analytical chemistry has been involved in this scientific evolution. Proteomics and metabolomics are emerging fields that require separation, identification, and quantification of proteins, peptides, and small molecules of metabolites in complex biological samples. The success of this work relies on efficient chromatographic and electrophoretic techniques, and on mass spectrometric detection. This paper reviews recent developments in the use of monolithic columns, focusing on their applications in "top-down" and "bottom-up" approaches, including their use as supports for immobilization of proteolytic enzymes and their use in two-dimensional and multidimensional chromatography. Whereas polymeric columns have been predominantly used for separation of proteins and polypeptides, silica-based monoliths have been more extensively used for separation of small molecules of metabolites. Representative applications in proteomics and in analysis of plant metabolites are given and summarized in tables.
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ABSTRACT: A novel (3-sulfopropyl methacrylate potassium)-silica hybrid monolithic column for capillary electrochromatography (CEC) has been prepared by a simple one-pot approach based on efficient thiol-ene click chemistry. In this process, the polycondensation of hydrolyzed alkoxysilanes and in situ click reaction of vinyl groups on 3-sulfopropyl methacrylate potassium (SPMA) and thiol groups on the precondensed siloxanes simultaneously occured in a pretreated capillary. Homogeneous monolithic matrix with large through-pores tightly bonded to the inner wall of the capillary was shown by optical microscope and scanning electron microscope (SEM). The minimum plate height of this hybrid monolithic column was determined as 3.9 μm for thiourea. Anilines, alkylbenzenes and phenols were well separated on this hybrid monolithic column by CEC, which indicated typical reversed-phase and cation-exchange chromatographic retention mechanisms of the column.
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