Open column chromatography is an excellent and easy technique for large-scale preparation and purification at low cost. Normal phase conditions are traditional in open column chromatography. Recently several attempts have been made to apply reversed phase technique to open column chromatography because of its numerous advantages.
However the so far available reversed phase packing materials could not perform well over 30-50% water concentration in the mobile phase.
The COSMOSIL^® C₁₈-OPN is not subject to such restrictions and the use of 100% aqueous effluents results in excellent separation. The COSMOSIL^® C₁₈-OPN is a new type of reversed phase C₁₈ packing material designed for open column chromatography.

Characteristics

The COSMOSIL^® C₁₈-0PN packing material is coated with hydrophilic groups to improve the affinity for highly polar effluents. The hydrophobic groups in the pore of the packing material provide superior retention characteristics in reversed phase partition chromatography.

Material characteristics

	75C₁₈-OPN	140C₁₈-OPN
Silica gel	totally porous spherical silica
Average particle size	75µm	140µm
Average pore size	approx. 120Å
Specific surface area	approx. 300m²/g
Stationary phase	octadecyl group
Application	open column chromatography,s flash column chromatography

Reproducibility and washing methods

Wash the COSMOSIL^® C₁₈-OPN packing material with tetrahydrofuran, chloroform or other solvents that can remove impurities absorbed onto the packing material. This packing material has excellent reproducibility and can be used repeatedly.

"CAUTION"
Do not wash with basic solvents of > pH 7 which will dissolve the silica gel or < pH 2 which will cleave the C₁₈ stationary phase. Dry the packing material at 50°C.

Influence of particle size

Comparison table of 75µm and 140µm

Particle (m)	Flow rate (ml/min)	Theoretical plate number			Rs		Separation time(min)	Consumption of solvent (ml)
Particle (m)	Flow rate (ml/min)	TB	TP	CF	TB/TP	TP/CF	Separation time(min)	Consumption of solvent (ml)
75	0.25	400	390	340	1.00	1.74	240	60
140	0.60	300	280	260	0.90	1.40	100	60

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Ordering information

Product name	Size	Code No.
COSMOSIL^® 75C₁₈-OPN	100g	37842-66
	500g	37842-95
	1kg	37842-11
COSMOSIL^® 140C₁₈-OPN	100g	37878-16
	500g	37878-45
	1kg	37878-61