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What's L-column ?
 Preeminent deactivation processing technology - Super End capping -
<Patent No.5,134,110 U.S.A>
Usually, endcapping is carried out using trimethylchlorosilane(TMS) or
hexa- methyldisilazane(HMDS) in liquid phase.But in this liquid phase reaction, silanol cannot be deactivated
completely. Endcapping of L-column is performed by high-temperature gaseous-phase silanization
(Super endcapping). Consequently, this endcapping technology prevents the tailing of the polar compound's peak
and shows very high durability even with an alkaline mobile phase, because of the strong film covering the silica
gel surface.
The usual ODS column is made produced by the following method
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(1) Silica gel surface
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(2) Octadesylsilylating processing
Chemical bonding of the ODS to the silica gel surface is carried out.
The residull silanol on the silica gel surface is deactivated. However,
the silanol cannot be octadecylsilylated completely (Theoretically only
up to a maximum of ca. 40% and free silanol still remains.) |
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(3) Deactivation (End capping)
Endcapping is carried out using trimethylchlorosilane(TMS) or hexamethyldisilazane(HMDS)
in liquid phase.
The residual silanol cannot be deactivated completely by the usulal deactivation
method. |
End capping of L-column ODS
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(1) Silica gel surface |
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(2) L-column Octadesylsilylating processing
Chemical bonding of the ODS to the silica gel surface is carried out. (Polymeric) |
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(3) Deactivation of L-column (Super end capping)
End capping of the L-column is performed by high- temperature gaseous-phase silanization. It this procedure neary completely deactivates the residual silanol on the silica gel surface. |
High purity Silica gel and Packing Technology
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L-column is produced using high-purity silica gel with few metallic impurities. Because of the preeminent endcapping method and the use of high-puriti silica gel, L-column is effective for the analysis of complex compounds influenced by the methal of the silica gel surface.
Moreover, full-spherical silica gel is used in the production of L-column, and its particle size distribution width is narrow. Therefore, the column pressure of L-column is low.
Specifications of Silica particles (5um)
Av. perticle size 5 um
Av. pore size 12 nm
Surface area 340m2/g
Pore volume 1.1mL/g
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Quality ontrol
L-column satisfies the requirements of the International Standard (ISO 9001) for a quality system and is manufactured under stringent control.
L-column is manufactured using high-purity silica gel, and its physical properties, such as the particle size distribution, average particle size, pore size and the surface area, were controlled strictly for every manufactured lot. Then, the octadecylsilylating and deactive processings (endcapping) were performed.
The column performance was evaluated by the following tests, (1) the carbon
content before and after endcapping, (2)measurement of the retention time
and the peak shape using acid, neutral and basic compounds, for every manufactured
lot. Furthermore, performance inspection (the number of theoretical plates,
peak symmetry, and retention time) was carried out for every column, and
only columns which passed inspection were shipped.
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Cirtificate |
of Resistration |
 L-column Top |
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ChromatoWEB
/ CERI Tokyo Laboratory Chromatography Department
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