Silica Gel Packing Agent (NH2, C18 Modified)

Silica gel has a strong physical strength and is the most widely used as a column packing agent for analysis and purification in chromatographies such as HPLC, medium and low pressure chromatography, and open column chromatography.

In general, there are unmodified silica gel and chemically modified silica gel that has been changed their functions by binding of various functional groups (C18, NH2 etc.) to the silanol groups on the surface of silica gel.

FUJIFILM Wako provides lineups of NH2/C18 packing agents prepared by binding an aminopropyl (NH2)/octadecyl (C18) group to crushed silica gel (Wakogel® series) or spherical silica gel (Wakosil® series).

Click here for packing agents for HPLC.

How to Select Silica Gel

  1. Shape

In general, spherical silica gel is expected to improve resolution and reproducibility compared with crushed silica gel (reasonable price).
FUJIFILM Wako employs crushed silica gel for Wakogel® series and spherical silica gel for Wakosil® series.

  1. Chemical Modification

Chemical modification is to bind various functional groups to silanol groups on the surface of silica gel to change silica gel functions. C18 modified silica gel (ODS) is an octadecyl group-bound silica gel and is suitable for reverse-phase chromatography. NH2 modified silica gel is an aminopropyl group-bound silica gel and is suitable for normal-phase, hydrophilic interaction, and ion exchange chromatography. Unmodified silica gel is mainly used for normal-phase chromatography.

  1. Particle Size

The larger the particle size, the more suitable for open columns, and the smaller the particle size, the more suitable for flash chromatography or HPLC.

  1. Pore Size and Specific Surface Area

The smaller the pore size, the larger the specific surface area of silica gel and the higher resolution of small molecules. On the other hand, the larger the pore size, the higher the resolution of high molecules such as proteins. Suitable pore size must be selected so that sample molecules retain the silica gels well.

Flow Chart for Selection of Silica Gel

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Particle Size Distribution Table

The smaller the particle size, the higher the resolution. However, the analysis time becomes longer due to slow flow rate. On the other hand, the larger the particle size, the flow speed becomes faster, and the behavior is suitable for open columns.

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List of Physical Properties for each Silica Gel Grade

Silica gel for general purpose (NH2 modified)
Product Name Shape Size Pore Size Pore Capacity Specific Area pH Intended Use Features
Wakogel® 50NH2
Wakogel® 50NH2 Crushed 38~63 μm 6.5 nm 0.7 mL/g 450 m2/g 8.5~11.5 Open column, medium pressure, flash chromatography Silica gel chemically modified with an aminopropyl group and is suitable for separation and purification in normal-phase, hydrophilic interaction, and ion exchange chromatography. It also has the features that it can fractionation of sugars and suppress tailing of basic compounds. Shape: Crushed silica gel modified with an aminopropyl group
Use: Open column, medium pressure, flash chromatography
Wakosil® 50NH2 
Wakosil® 50NH2 (HC) Spherical 35~63 μm - - 900 m2/g 8.5~11.5 Open column, medium pressure, flash chromatography Silica gel chemically modified with an aminopropyl group and is suitable for separation and purification in normal-phase, hydrophilic interaction, and ion exchange chromatography. It also has the features that it can fractionation of sugars and suppress tailing of basic compounds. Because its specific surface area is larger than Wakogel® 50NH2, it has high retention performance and large sample loading capacity.
Shape: Spherical silica gel modified with an aminopropyl group
Use: Open column, medium pressure, flash chromatography
Silica gel for general purpose (C18 modified)
Product Name Shape Size Pore Size Pore Capacity Specific Area pH Intended Use Features
Wakosil® C18 series
Wakosil® 25C18 (1530 μm 70% up) Spherical 15~30 μm 12 nm 1 mL/g 330 m2/g - Open column, medium pressure, flash chromatography Silica gel chemically modified with a C18 groups (ODS). It is suitable for separation and purification in reverse-phase chromatography, and a wide range of eluents from organic solvents to aqueous solutions can be used. The number before C18 = the particle sizeShape: Spherical silica gel modified with a C18 groups. (ODS)
Use: Open column, medium pressure, flash chromatography
Wakosil® 40C18 (30〜50 μm 70% up) 30〜50 μm
Wakosil® 50C18 38~75 μm 1.2 mL/g 280 m2/g
Wakosil® 100C18 63~212 μm 300 m2/g Open column

NH2 modified Silica Gel

Wakogel® 50NH2

Wakogel® 50NH2 is the chemically modified with an aminopropyl group crushed silica gel and is suitable for separation and purification in normal-phase, hydrophilic interaction, and ion exchange chromatography. It also has the features that it can fractionation of sugars and suppress tailing of basic compounds.

Product Name Shape Particle Size Pore Size Pore Capacity Specific Area pH Intended Use
Wakogel® 50NH2 Crushed 38~63 μm 6.5 nm 0.7 mL/g 450 m2/g 8.5~11.5 Open column, medium pressure, flash chromatography

Wakosil® 50NH2 (HC)

Wakosil® 50NH2 (HC) is the chemically modified with an aminopropyl group spherical silica gel and is suitable for separation and purification in normal-phase, hydrophilic interaction, and ion exchange chromatography. It also has the features that it can fractionation of sugars and suppress tailing of basic compounds. Because its specific surface area is larger than Wakogel® 50NH2, it has high retention performance and large sample loading capacity.

Product Name Shape Particle Size Specific Area pH Intended Use
Wakosil® 50NH2 (HC) Spherical 35~63 μm 900 m2/g 8.5~11.5 Open column, medium pressure, flash chromatography

C18 modified Silica Gel

Wakosil® C18 Series

Wakosil® C18 series is the C18 groups-modified silica gel (ODS) and is suitable for separation and purification in reverse-phase chromatography, and a wide range of eluents from organic solvents to aqueous solutions can be used.

In addition, the analytical conditions for the ODS (C18) column, which is widely used in HPLC, can be applied to the setting of fractionation conditions, and the setting of conditions is easier than the shift to fractionation with unmodified silica gel.

Physical Property Information

Product Name Shape Particle Size Pore Size Pore Capacity Specific Area Intended Use
Wakosil® 25C18 (15〜30 μm 70% up) Spherical 15~30 μm 12 nm 1 mL/g 330 m2/g Open column, medium pressure, flash chromatography
Wakosil® 40C18 (30〜50 μm 70% up) 30~50 μm

Sample distribution of Capsaicin Using Wakosil® 25C18

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Column : Wakosil® 25C18
Column Size : 50 mm x 250 mm
Eluent : A) CH3OH/H2O=50/50 (v/v)
    B) CH3OH/H2O=80/20 (v/v)
      0→90 min. B 0→50%
      90 min. B 100%
Flow Rate : 120 mL/min. at R.T.
Detection : UV 280 nm
Sample : Capsicum extract 11 mL

Separation and Purification of Saikosaponin Using Wakogel®

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HPLC chromatogram in each purification step

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Product List

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NH2 Modified Silica Gel

C18 Modified Silica Gel

For research use or further manufacturing use only. Not for use in diagnostic procedures.

Product content may differ from the actual image due to minor specification changes etc.

If the revision of product standards and packaging standards has been made, there is a case where the actual product specifications and images are different.

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