ODS (Octadecylsilane) Columns
3-10 μm
120Å / 300Å
Wide pH Range (1-12.5)
Availability: In Stock
C18 HPLC Columns
Description
A C18 HPLC column (octadecylsilane, ODS) is the most widely used reversed-phase stationary phase, offering strong hydrophobic retention for non-polar to moderately polar compounds.
Hawach C18 columns are available in five specialized chemistries to address specific separation challenges:
- C18-Aqueous -100% aqueous mobile phase resistant, no phase collapse. Ideal for polar and water-soluble compounds that are poorly retained on standard C18.
- C18-Universal -Classic C18 with double end-capping, wide pH range (1.5-10), sharp peak shapes. Direct replacement for Waters Symmetry C18, Agilent Zorbax XDB C18, Phenomenex Luna C18, and many others.
- C18-Low pH -Extremely stable at pH 0.5-8, not end-capped, retains polar compounds via silanol interactions. Substitute for Agilent Zorbax SB-
- C18-Alkaline -Embedded hydrophilic groups to shield silanols, excellent peak shape for basic compounds. Mixed-mode retention (hydrophobic + electrostatic).
- C18-X -High pH tolerance (1-5), combines silica efficiency with polymer-like stability. Available in 120Å and 300Å pore sizes.
All Hawach C18 columns provide exceptional lot-to-lot reproducibility, long lifetime, and competitive pricing.
Why Hawach C18 columns rank for HPLC method development
- Five distinct C18 selectivities -choose by aqueous compatibility, pH range, or basic compound peak shape
- Wide particle size range -3, 5, 10 μm; diameters 2.1-8 mm; lengths 30-300 mm
- 300Å pore size options for large biomolecules (peptides, proteins)
- pH stability from 1 to 12.5 across the series
- 100% aqueous mobile phase compatible (Aqueous & Low pH models)
- Lowest pH 0.5 tolerance (Low pH column) -most stable C18 for low-pH applications
- Direct replacements for major brands: Waters, Agilent, Phenomenex, Sigma, YMC
Conversion Compression Block (Decision Shortcut)
| If your application involves… | Recommended Phase | Key Feature |
| Highly polar / water-soluble compounds, 100% aqueous mobile phase | C18-Aqueous | No phase collapse, increased polar retention |
| General method development, most routine separations | C18-Universal | Double end-capped, wide pH 1.5-10, best value |
| Low pH (<2) mobile phase (e.g., 0.1% TFA), high temperature | C18-Low pH | Stable at pH 0.5-8, not end-capped, polar retention |
| Basic compounds (amines) with tailing issues | C18-Alkaline | Embedded hydrophilic groups, excellent basic peak shape |
| High pH (up to 12.5) stability, long lifetime | C18-X | High pH tolerance, silica-polymer hybrid |
| Peptides / proteins (large molecules) | Any C18 with 300Å pore | Suitable for macromolecules |
C18 Phase Comparison – Which One Fits Your Method?
| Feature | C18 – Aqueous | C18 – Universal | C18 – Low pH | C18 – Alkaline | C18 – X |
| pH range | 1.5-10 | 1.5-10 | 0.5-8 | 2-8 | 1-12.5 |
| 100% aqueous | Yes | ≤95% | Yes | ≤95% | ≤95% |
| End-capping | Double | Double | Not end-capped | – | Yes |
| Selectivity | Less retentive than Universal for non-polar; retains polar analytes | Classic C18, most retentive | More polar than Universal; silanol interactions | Mixed mode (hydrophobic + electrostatic) | High pH stable, similar to Universal |
| Best for | Polar, water-soluble compounds | General purpose, most common methods | Low pH, high temp, polar compounds | Basic compounds (amines, alkaloids) | High pH mobile phases, long column life |
| Particle sizes | 3, 5, 10 μm | 3, 5, 10 μm | 3, 5 μm | 5 μm | 3, 5, 10 μm |
| Pore sizes | 120Å (300Å opt) | 120Å, 300Å | 120Å (300Å opt) | 120Å | 120Å, 300Å |
10-Second Selection Guide by Application
| Application | Recommended Phase | Recommended Dimensions |
| General pharmaceutical impurity analysis | C18-Universal | 4.6×150 mm, 5 μm |
| Polar metabolites, water-soluble vitamins | C18-Aqueous | 4.6×150 mm, 5 μm |
| Low pH mobile phase (e.g., 0.1% phosphoric acid) | C18-Low pH | 4.6×150 mm, 5 μm |
| Basic drugs (e.g., tricyclic antidepressants, β-blockers) | C18-Alkaline | 4.6×150 mm, 5 μm |
| High pH mobile phase (e.g., pH 10-12) | C18-X | 4.6×150 mm, 5 μm |
| LC/MS (high sensitivity, low flow) | Any C18 with 3 μm, 2.1 mm ID | 2.1×50-100 mm |
| Peptide / protein separations | Any C18 with 300Å pore | 4.6×250 mm, 5 μm |
| Preparative scale purification | Any C18 in 6.0-7.8 mm ID | 7.8×250 mm, 5-10 μm |
Core Technical Specifications
| Parameter | C18 – Aqueous | C18 – Universal | C18 – Low pH | C18 – Alkaline | C18 – X |
| Bonded phase | Octadecylsilane | Octadecylsilane | Octadecylsilane (bulky protecting groups) | Octadecylsilane + hydrophilic groups | Octadecylsilane (high-density) |
| Surface area | ~300 m²/g | ~300 m²/g | ~300 m²/g | ~300 m²/g | 320 m²/g |
| Carbon load | ~17% | ~17-19% | ~15% | ~16% | 14% |
| End-capping | Double | Double | No | Yes | Yes |
| USP classification | L1 | L1 | L1 | L1 | L1 |
| Max pressure | 4000-6000 psi | 4000-6000 psi | 4000-6000 psi | 4000-6000 psi | 4000-6000 psi |
| Temperature | ≤60°C | ≤60°C | ≤60°C | ≤60°C | ≤60°C |
Key Performance Advantages by Phase
C18-Aqueous
- 100% aqueous mobile phase resistant -no phase collapse, longer column lifetime
- Increased retention for polar compounds -retains water-soluble analytes that normally elute at void volume on standard C18
- Double end-capped -sharp peaks for acids and bases
- Less retentive than C18-Universal for non-polar compounds
C18-Universal
- Most versatile C18 -replaces Waters Symmetry, Agilent Zorbax XDB, Phenomenex Luna, and many others
- Double end-capping -excellent peak shape for basic, acidic, and neutral compounds
- High efficiency and reproducibility -ideal for traditional Chinese medicine, environmental, and food safety testing
- Available in 120Å and 300Å pore sizes
C18-Low pH
- Extreme low pH stability (0.5-8) -most stable C18 for low-pH conditions (e.g., 0.1% TFA, formic acid)
- Not end-capped -retains polar early-eluting compounds via silanol interactions
- Endures 100% water -same aqueous compatibility as C18-Aqueous
- Direct substitute for Agilent Zorbax SB-C18
- 300Å version for polypeptide and protein separations
C18-Alkaline
- Embedded hydrophilic groups -shield silanol groups, prevent secondary interactions with basic compounds
- Excellent peak shape for amines, alkaloids -reduces tailing
- Mixed-mode selectivity (hydrophobic + electrostatic) -orthogonal to traditional C18
- Faster separation of similar compounds
C18-X
- High pH tolerance (1-5) -combines silica efficiency with polymer stability
- Long lifetime under basic mobile phase conditions (e.g., ammonium hydroxide)
- High carbon load (14%) -good retention
- Available in 3, 5, 10 μm particles
Separation Effect – Typical Chromatograms
C18-Universal
C18 Low pH
C18 Alkaline
C18-Aqueous
Ordering Information
Full SKU lists available in our PDF catalog – email info@hawach.com for complete details.
| Phase | Particle Size | Pore Size | ID (mm) | Length Range (mm) | Cat# Range / Specific Cat# |
| C18-Aqueous | 3 μm | 120Å | 2.1, 3.0, 4.0, 4.6 | 30-250 | 13011001 – 13011036 |
| 5 μm | 120Å | 2.1, 3.0, 4.0, 4.6, 6.0, 6.5, 7.8 | 30-300 | 13011037 – 13011082 | |
| 10 μm | 120Å | 3.9, 4.0, 4.6 | 150-300 | 13011083 – 13011088 | |
| C18-Universal | 3 μm | 120Å | 2.1, 3.0, 4.0, 4.6 | 30-250 | 13011089 – 13011124 |
| 3 μm | 300Å | 2.1, 3.0, 4.0, 4.6 | 50-250 | 13011125 – 13011138 | |
| 5 μm | 120Å | 2.1, 3.0, 4.0, 4.6, 6.0, 6.5, 7.8 | 30-300 | 13011139 – 13011183 | |
| 5 μm | 300Å | 2.1, 3.0, 4.0, 4.6 | 50-250 | 13011184 – 13011198 | |
| 10 μm | 120Å | 3.9, 4.0, 4.6 | 150-300 | 13011199 – 13011205 | |
| C18-Low pH | 3 μm | 120Å | 2.1, 3.0, 4.0, 4.6 | 30-250 | 13011206 – 13011241 |
| 5 μm | 120Å | 2.1, 3.0, 4.0, 4.6, 6.0, 6.5, 7.8 | 30-300 | 13011242 – 13011287 | |
| 5 μm | 300Å | 4.6 | 250 | 13011288 | |
| C18-Alkaline | 5 μm | 120Å | 4.6 | 150 | 13011289 |
| 5 μm | 120Å | 4.6 | 250 | 13011290 | |
| C18-X | 3 μm | 120Å | 4.6 | 75 | 13021503 |
| 3 μm | 120Å | 4.6 | 100 | 13021691 | |
| 3 μm | 120Å | 4.6 | 125 | 13021522 | |
| 3 μm | 120Å | 4.6 | 250 | 13021774 | |
| 5 μm | 120Å | 4.6 | 150 | 13021424 | |
| 5 μm | 120Å | 4.6 | 250 | 13021411 | |
| 5 μm | 120Å | 6 | 150 | 13021582 |
For dimensions not listed, custom lengths and IDs available on request.
Download PDF Datasheet
Typical Applications
| Application | Recommended Phase | Why |
| Polar water-soluble vitamins | C18-Aqueous | Retains compounds lost on standard C18 |
| General API and impurity profiling | C18-Universal | Widest applicability, good peak shape |
| Peptide mapping (large molecules) | Any C18 with 300Å pore | Prevents pore exclusion |
| Basic drug analysis (e.g., metformin, propranolol) | C18-Alkaline or C18-Universal | C18-Alkaline minimizes tailing |
| Acidic mobile phase (pH 1.5-2) | C18-Low pH | Extended column lifetime |
| High pH method (pH 10-12, e.g., amine separations) | C18-X | Stable at high pH |
Chemical Compatibility & Mobile Phase Guidelines
Compatible with:
- Aqueous buffers (acetate, phosphate, formate, Tris)
- Organic modifiers: acetonitrile, methanol, ethanol, THF (≤10%)
- Acidic additives: TFA (≤0.2%), formic acid (≤0.2%), phosphoric acid (≤0.1%)
- Basic additives: ammonium hydroxide, triethylamine (≤0.1%) -note C18-X tolerates higher concentrations
Not recommended for:
- 10% THF (may damage packing)
- 80°C operation
Chlorinated solvents (dichloromethane, chloroform) as mobile phase
Strong bases (>pH 8) on non-X columns – use C18-X for high pH
Manufacturing & Quality System
- ISO 9001 controlled production
- Proprietary surface modification for smooth, uniform, inert silica
- Unique bonding chemistry and end-capping technology
- Each column individually tested and supplied with COA and test chromatogram
- Exceptional lot-to-lot reproducibility
- Full lot traceability
- OEM private label and custom dimensions available
Procurement Decision Block
Why procurement teams choose Hawach C18 columns:
- Best value -premium quality at very competitive prices
- Five specialized chemistries -one supplier covers 90% of C18 method needs
- Direct replacements for Waters, Agilent, Phenomenex, Sigma, YMC -no method revalidation
- Wide dimension range -analytical to preparative scales
- Stable supply chain -in-stock popular dimensions
- Full documentation -COA, test chromatogram, batch traceability for GMP/GLP
FAQ
What is the difference between C18 and ODS?
ODS (Octadecylsilane) is the chemical name for C18. They are the same thing. Hawach C18 columns are fully equivalent to ODS columns.
Which C18 column should I start with for method development?
Start with C18-Universal. It covers most routine separations. If you have polar compounds that elute too early, try C18-Aqueous. For low pH (<2), use C18-Low pH. For basic compounds with tailing, try C18-Alkaline. For high pH (>8), use C18-X.
Can I use 100% water as mobile phase?
Yes – C18-Aqueous and C18-Low pH columns are designed for 100% aqueous mobile phase without phase collapse. Standard C18 columns (Universal, Alkaline, X) should not exceed 95% water.
What pore size should I choose for peptide/protein analysis?
Use 300Å pore size for molecules larger than ~10 kDa. Hawach offers 300Å versions for C18-Universal and C18-Low pH.
Do you offer guard columns?
Yes – standard guard cartridges and holders are available for all column IDs.
What is the maximum pressure for 3 μm columns?
~6000 psi (400 bar) – suitable for UHPLC and conventional HPLC.
Do you offer custom dimensions (non-standard lengths/IDs)?
Yes – minimum order quantity applies. Contact OEM team for custom dimensions.
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