Simple and Comprehensive Two-Dimensional Reversed-Phase HPLC Using Monolithic Silica Columns

Tanaka, Nobuo; Kimura, Hiroshi; Tokuda, Daisuke; Hosoya, Ken; Ikegami, Tohru; Ishizuka, N.; Minakuchi, Hiroyoshi; Nakanishi, Koji; Shintani, Yukihiro; Furuno, Masahiro; Cabrera, Karin

doi:10.1021/ac034925j

Cited by 136 publications

(76 citation statements)

References 32 publications

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“…70 Every fraction from the 1st-D column, 15 cm long (4.6 mm i.d. ), packed with fluoroalkylsilyl-bonded (FR) silica particles (5 µm), was subjected to separation in 2nd-D using octadecylsilylated (C18) monolithic silica columns (4.6 mm i.d.,…”

Section: ·1 Rp-rp 2d-hplc Using Two Different Columnsmentioning

confidence: 99%

Properties of Monolithic Silica Columns for HPLC

et al. 2006

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Monolithic silica columns and their use in high peak-capacity HPLC separations are reviewed. Monolithic silica columns can potentially provide higher overall performance than particle-packed columns based on the variable external porosity and variable through-pore size/skeleton size ratios. The high permeability of monolithic silica columns resulting from the high porosity is shown to be advantageous to generate large numbers of theoretical plates with long capillary columns. High permeability together with the high stability of the network structures of silica allows their use in high-speed separations required for a second-dimension column in two dimensional HPLC. Disadvantages of monolithic silica columns are also described.

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Section: ·1 Rp-rp 2d-hplc Using Two Different Columnsmentioning

confidence: 99%

Properties of Monolithic Silica Columns for HPLC

et al. 2006

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“…As each analysis on ''2nd-D column A'' or ''2nd-D column B'' is finished within 60 seconds, the repeated analysis until the end of elutions on the first dimension constitutes the 2-dimensional separations. 39,40 Another run with reversed distribution order in the second dimension completes the total set of 2D separations.…”

Section: Monolithic Silica Columnsmentioning

confidence: 99%

Sol–Gel Process of Oxides Accompanied by Phase Separation

Nakanishi¹

2006

Bulletin of the Chemical Society of Japan

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A versatile sol-gel method for fabricating porous oxide materials with well-defined co-continuous macropores has been reviewed. The chemical instability, in many cases induced by polymerization of the network-forming components, triggers the formation of biphasic morphologies, followed by an irreversible freezing of the transient morphology by the sol-gel transition of the gelling phase. Upon removal of the non-gelling phase, an oxide framework comprising of controlled macropores can be obtained. The mesopore system of such macroporous materials can be further modified either by a physico-chemical treatment or a supramolecular templating technique. Pure silica and siloxane-based organicinorganic hybrids with a hierarchical pore system in monolithic form have been successfully applied to the novel type of separation medium for high performance liquid chromatography, HPLC. Additional topics are also described including recent advances in the 3D-analysis of the interfacial properties of macroporous systems, extended compositional variations in the network-forming phase, and emerging applications in areas of biochemistry.In the preparation of amorphous materials, the unstable or metastable state plays an important role in forming multi-phasic structures in the length scale longer than several nanometers. While in metastable states one often observes a formation of dispersed phases associated with thermally activated diffusion, unstable states are the starting points of various spontaneous morphology formation processes represented by the spinodal decomposition. In melt-quenching fabrication processes of oxide glasses, a pseudo one-phase material is initially formed by rapidly cooling a multi-component melt, and partially crystallized or phase-separated microstructures are controlled by subsequent reheating processes. The metastable glassy state is conveniently used to bring a system into a thermodynamically unstable region as well as to physically freeze the transient heterogeneous state at will. In a chemically polymerizing system, however, the polymerization and crosslinking reactions take place in the presence of a solvent. It is virtually impossible to physically freeze the reaction without influencing all the chemical interactions among the constituents. A continuous polymerization process is chemically equivalent to the continuous physical cooling with respect to the chemical interaction (mutual solubility) and material transport (mobility of the solutes). That is, the polymerizing system resulting in a sol-gel transition is a chemical analogue to a continuously cooled system resulting in a glass transition. If a process of developing heterogeneity in the system superposes a structurefreezing process, a competition will take place between the two processes. Various kinds of transient heterogeneous structures will be frozen in the resultant solidified materials.Phase-separation phenomena related to the heterogeneity formation in materials have been investigated first in metallic alloys and oxide glasses, follow...

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“…33,34) In the near future, a two dimensional micro HPLC system using monolithic silica capillary column is expected to be available. 35,36) Another approach for solving the ion suppression problem is the utilization of a stable isotope dilution-based comparative quantification, which is the most convenient practical solution. The principle of the method is that isotopomers of target metabolites are used as internal standards to normalize analysis variation, particularly for ionization.…”

Section: Instrumental Analysismentioning

confidence: 99%