Chromasol ONYX C18 HPLC Column – USP – L1

Technical Details — Chromasol ONYX C18 (USP L1)

1. Stationary Phase / Chemistry

   • Bonded phase: Octadecylsilane (C18).

   • USP classification: L1 (standard C18).

   • End-capping: Yes — minimizes residual silanol interactions.

2. Support / Particle Properties

   • Base material: Porous pure silica, spherical particles.

   • Particle size options: 1.7 µm, 1.9 µm, 2 µm, 3 µm, 5 µm, 10 µm.

   • Pore sizes available: 100 Å, 150 Å, 200 Å, 300 Å.

   • Surface area: Varies depending on pore size — 330, 176, 148, 110 m²/g (for the respective pore sizes).

   • Pore volume: ~0.80 mL/g.

3. Carbon Loading / Ligand Density

   • Carbon content: ~19% by weight.

   • Higher carbon loading relative to some other media → generally gives stronger retention / hydrophobic interaction.

4. Chemical Stability

   • pH stability range: 2 – 10 (tested for both acid and base stability).

   • Temperature tolerance: Up to 90 °C (ambient to 90 °C as per spec).

5. Performance / Efficiency

   • According to Intek, ONYX C18 shows “higher efficiency” — e.g., for 4.6 × 250 mm, 5 µm column, they report ~22,660 theoretical plates (N) with a % RSD of ~2.7.

   • Good peak shape: tailing factor ~1.04 with % RSD = 2.2 (for specific test) as per Intek.

   • Robustness: Very stable under aggressive acid (pH ~1.2) and alkaline (pH ~10) test conditions (16h) per Intek’s internal testing.

6. Applications

   • Pharmaceutical / Analytical HPLC: Because of its robustness and good efficiency, it’s well-suited for pharmaceutical assay, method development, and routine QC.

   • Scale-up / Preparative: There are semi-preparative and preparative versions of ONYX C18:

     • Semi-prep: 10 × 250 mm, 5 µm — plates ~26,673, TF ~1.08.

     • Prep: e.g., 21.2 × 150 mm, 5 µm (N ~17,797, TF ~1.02) and 30 × 250 mm, 10 µm (N ~13,163, TF ~1.06).

7. Advantages / Unique Selling Points

   • Lower surface area (relative to JADE): As per Intek, ONYX has a lower surface area (compared to their JADE brand), but higher carbon loading, which gives a different retention/interaction profile.

   • Robust pH stability: Ability to withstand both acidic and basic mobile phases / cleaning.

   • Reusable for method equivalency: Intek suggests ONYX is useful for “brand equivalence” in method development — if you’re comparing with columns from other brands, ONYX may replicate or come close to their performance..

8. Limitations / Considerations

   • As with any C18 column, the choice of particle size, length, and internal diameter will affect backpressure — smaller particles (1.7, 1.9, 2 µm) → higher pressure, so ensure your HPLC system can handle it.

   • Even though it supports up to pH 10, frequent exposure to extremes should be done carefully, with proper flushing, to maximize column life.

   • Storage and maintenance: Use recommended solvents, and possibly a guard column for dirty or complex samples.