Standard Reversed Phase Columns
The reversed phase HPLC column is most commonly used because of the high theoretical plate number, excellent separation characteristics, reproducibility, affordable cost and ease of use. Columns packed with the octadecyl group bonded type silica gel (C18, ODS) are the most widely employed. We offer three types of octadecyl group bonded columns: COSMOSIL 3C18-EB, C18-MS-II, C18-AR-II and C18-PAQ, each of which has a different separation property.
|Silica Gel||High Purity Porous Spherical Silica|
|Average Particle Size||3 µm||3, 5, 15 µm||5, 15 µm|
|Average Pore Size||approx. 120 Å|
|Specific Surface Area||approx. 300 m2/g|
|Main Interaction||Hydrophobic Interaction|
|End Capping Treatment||Near-perfect Treatment|
|Carbon Content||approx. 14.5%||approx. 16%||approx. 17%||approx. 11%|
|Feature||This phase with a better end-capping treatment offers improved peak shape
and separation particularly
for basic compounds.
|This phase is recommended for most applications but particularly effective for basic compounds.||This phase is recommended for separations requiring acidic mobile phase conditions. It also shows superior molecular shape selectivity to monomeric type C18columns.||This phase is designed to offer superior retention of polar compounds and excellent reproducibility in highly aqueous mobile phases, even in 100% aqueous.|
Optimum pH range of columns based on silica gel is between 2 and 7.5.
Column Selection by Mobile Phase
- If a mobile phase is determined, use the following chart to select an appropriate COSMOSIL column.
- Refer to application data above for choosing a mobile phase of new analysis.
- Adjustment of pH is required for dissociative compounds.
- Generally acidic mobile phase is suitable for acidic compounds, and neutral mobile phase is suitable for basic compounds.
- If you are not sure about the mobile phase, try C18-MS-II first.
Deference of Separation Property
|Column Size||4.6 mm I.D. x 150 mm||Sample||1. Valerophenone||(0.17 µg)|
|Mobile Phase||Methanol : Water = 80 : 20||2. Butyl Benzoate||(0.17 µg)|
|Flow Rate||1.0 ml/min||3. Butylbenzene||(8.0 µg)|
|Detection||UV 254 nm||5. Amylbenzene||(8.0 µg)|
|6. Triphenylene||(0.021 µg)|
Column Selection Based on Application
We prepare following application data to help you select separation conditions.
COSMOSIL Application, which includes more than 7,000 applications using COSMOSIL columns, is now available.
The application is searchable by sample category, sample name, CAS No., column name and particle size.
Application of USP Standars using COSMOSIL columns in accordance with the conditon specfied in USP-PF(Pharmacopoeial Forum) online is available.
Data of drugs using three kinds of C18 columns that are specified in HPLC analysis in Application Data of Substances in Japanese Pharmacopoeia, 15th version is available.