COSMOSIL 3C18-SS
COSMOSIL 3C18-SS is the product of perfecting our chemical modification and endcapping technology, enabling this column to withstand alkaline and acidic mobile phases. It also resists peak tailing, and with the 3 µm particle size, fast and efficient analysis is possible on conventional instruments. It is recommended as a general-use column, especially for method development in which the analysis conditions are uncertain.
Applications
Oligonucleotides (basic mobile phase, high temperature)
By using an alkaline mobile phase under high temperatures with LC-MS, impurities from the oligonucleotide synthesis process (short-mers and P-S to P-O conversion impurities) could be separated from the full-length product.
| Sequence | |
|---|---|
| FLP: | 5'-A^T^C^G^G^G^G^A^G^G^G^C^T^T^A^C^C^A^T^C-3' |
| N-1: | 5'-A^T^C^G^G^G^G^A^G^G^G^C^T^T^A^C^C^A^T-3' |
| N-2: | 5'-A^T^C^G^G^G^G^A^G^G^G^C^T^T^A^C^C^A-3' |
| PS→PO, 19 mer: | 5'-A^T^C^G^G^G^G^A^G^G^G^C^T^T^A^C^C^A^T-C-3' |
| PS→PO, 18＆19 mer: | 5'-A^T^C^G^G^G^G^A^G^G^G^C^T^T^A^C^C^A-T-C-3' |
Phosphodiester bonds replaced with phosphorothioate bonds; [^] PS bond; [-] PO bond
| Conditions | |
|---|---|
| Column | COSMOSIL 3C18-SS, 2.0 mm I.D. × 150 mm |
| Mobile phase | A: 100 mM HFIP-15 mM Triethylamine (TEA) B: Solvent A / Acetonitrile / Methanol = 2 / 1 / 1 (v / v / v) B conc. 15 → 20% (0 → 20 min) |
| Flow rate | 0.2 mL/min |
| Temperature | 65°C |
| Sample conc. | 100 µM (FLP) and 25 µM (others) |
| Inj. vol. | 1 µL |
Peptides (acidic mobile phase, high temperature)
Using standard peptide analysis conditions, these 3 structurally similar compounds (α-defensin) could not be separated. However, by changing the mobile phase additive to formic acid and increasing the temperature, resolution (RS) of greater than 1.5 was achieved.
The difference in sequence is from a different or absent amino acid at the N-terminus.
Pairs of cysteine are bridged by disulfide bonds.
| Conditions | |
|---|---|
| Column | COSMOSIL 3C18-SS, 2.0 mm I.D. x 150 mm |
| Flow rate | 0.2 mL/min |
| Detection | 220 nm |
| Sample conc. | 20 µM |
| Injection vol. | 2 µL |
Comparison of durability with basic mobile phase
When used with a harshly basic mobile phase, most C18 columns degrade quickly. The below graphs show the retention time (tr) and theoretical plates (N), respectively, of the COSMOSIL 3C18-SS and two other columns under our accelerated test.
Column size: 2.0 mm I.D. × 100 mm (COSMOCORE: 2.1 mm I.D.)
Sample: Naphthalene
| Alkaline flow conditions | |
|---|---|
| Alkaline solution | Acetonitrile / 50 mM TEA (pH 11.8) = 10 / 90 |
| Flow rate | 0.2 mL/min |
| Temperature | 50°C |
| Analysis conditions | |
|---|---|
| Mobile phase | Acetonitrile / H2O = 50 / 50 |
| Flow rate | 0.2 mL/min |
| Temperature | 30°C |
Under the highly basic mobile phase conditions above, COSMOSIL 3C18-SS showed high durability. This column can be used under harsh conditions, overcoming the limitations of conventional silica-based columns.
Comparison of separation performance
COSMOSIL 3C18-SS was compared to hybrid silica and core-shell columns. Overall, COSMOSIL 3C18-SS demonstrated high efficiency and low backpressure, in addition to sharp peaks even for basic and metal-coordination compounds.
Retention behavior
Basic compound
Metal coordination compound
Specifications
| Packing material: 3C18-SS | |
|---|---|
| Silica gel | High-purity fully-porous spherical silica gel |
| Stationary phase | Octadecyl group |
| Average particle size | Approx. 3 µm |
| USP code | L1 |
| Average pore size | Approx. 12 µm |
| Maximum pressure | 30 MPa |
| Specific surface area | Approx. 300 m2/g |
| Usable pH range | 1–12 * |
* For longest lifetime, pH 2–10 is recommended.
Ordering information
| Product name | Size | Product no. | Price |
|---|---|---|---|
| COSMOSIL 3C18-SS analytical columns | 2.0 × 50 | 22560-61 |  |
| 2.0 × 75 | 22542-01 | ||
| 2.0 × 100 | 22543-91 | ||
| 2.0 × 150 | 22546-61 | ||
| 2.0 × 250 | 22547-51 | ||
| 3.0 × 50 | 22548-41 | ||
| 3.0 × 75 | 22549-31 | ||
| 3.0 × 100 | 22550-91 | ||
| 3.0 × 150 | 22551-81 | ||
| 3.0 × 250 | 22552-71 | ||
| 4.6 × 50 | 22553-61 | ||
| 4.6 × 75 | 22554-51 | ||
| 4.6 × 100 | 22555-41 | ||
| 4.6 × 150 | 22558-11 | ||
| 4.6 × 250 | 22559-01 | ||
| COSMOSIL 3C18-SS guard cartridges | 2.0 × 10 cartridge* | 22539-74 | |
| 4.6 × 10 cartridge* | 22540-34 |
* Two cartridges included.
Cartridge holder required:
- #11884-71 for 2.0 mm I.D.
- #19989-71 for 4.6 mm I.D.
