Silica Gel Packing Agent (NH₂, C18 Modified)

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.

2. 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.

3. 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.

4. 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

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.

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 (15〜30 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

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

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
Wakosil® 50C18		38～75 μm		1.2 mL/g	280 m2/g
Wakosil® 100C18		63～212 μm			300 m2/g	Open column