C18 HPLC Columns
USHD C18 HPLC Columns
USHD C18 is a reversed-phase octadecyl (C18) family, USP L1. Five phases differ by carbon load, pore size and pH range.
Use C18 or C18-Pro for general methods, C18-AQ for high-water mobile phases, C18-AR for low pH, and C18-T when the method needs pH up to 11.
Analytical HPLC column
Features
Five USP L1 C18 phases. Carbon load, pore size and pH range are the selection differences.
- USHD C18-Pro — 10% carbon, 200 m²/g, 150 Å, pH 2–8. Lower carbon load and a larger pore than the 120 Å C18 phases.
- USHD C18 — 17% carbon, 320 m²/g, 120 Å, pH 2–8. Higher carbon load for stronger retention.
- USHD C18-AQ — 12% carbon, 320 m²/g, 120 Å, pH 2–8. For polar compounds and high-water or 100% aqueous mobile phases.
- USHD C18-AR — 10% carbon, 320 m²/g, 120 Å, pH 0.5–8. For low-pH methods.
- USHD C18-T — 14% carbon, 320 m²/g, 120 Å, pH 1–11, on hybrid silica. For wide-pH and alkaline conditions.
Product Selection
Pick the phase from the pH range and carbon load, then match particle size and column dimensions.
Specifications
Phase specifications published for the USHD C18 family.
| Phase | USP | Particle Size | Pore Size | Surface Area | Carbon Load | pH |
|---|---|---|---|---|---|---|
| USHD C18-Pro | L1 | 5 μm, 3.5 μm | 150 Å | 200 m²/g | 10% | 2–8 |
| USHD C18 | L1 | 5 μm, 3 μm, 1.8 μm | 120 Å | 320 m²/g | 17% | 2–8 |
| USHD C18-AQ | L1 | 5 μm, 3 μm, 1.8 μm | 120 Å | 320 m²/g | 12% | 2–8 |
| USHD C18-AR | L1 | 5 μm, 3 μm, 1.8 μm | 120 Å | 320 m²/g | 10% | 0.5–8 |
| USHD C18-T | L1 | 5 μm, 3 μm, 1.8 μm | 120 Å | 320 m²/g | 14% | 1–11 |
Standard dimensions
Each phase is listed in 2.1×50, 2.1×100, 3.0×50, 3.0×100, 4.6×50, 4.6×100, 4.6×150 and 4.6×250 mm. Other lengths and internal diameters can be requested.
USHD C18-Pro
General reversed-phase work where a lower carbon load and 150 Å pore are preferred: pharmaceuticals, traditional Chinese medicine, food and environmental samples.
| Particle Size | Pore Size | Standard Dimensions |
|---|---|---|
| 5 μm | 150 Å | 2.1×50 mm, 2.1×100 mm, 3.0×50 mm, 3.0×100 mm, 4.6×50 mm, 4.6×100 mm, 4.6×150 mm, 4.6×250 mm |
| 3.5 μm | 150 Å | 2.1×50 mm, 2.1×100 mm, 3.0×50 mm, 3.0×100 mm, 4.6×50 mm, 4.6×100 mm, 4.6×150 mm, 4.6×250 mm |
USHD C18
Higher carbon load for stronger retention and selectivity on routine reversed-phase methods.
| Particle Size | Pore Size | Standard Dimensions |
|---|---|---|
| 5 μm | 120 Å | 2.1×50 mm, 2.1×100 mm, 3.0×50 mm, 3.0×100 mm, 4.6×50 mm, 4.6×100 mm, 4.6×150 mm, 4.6×250 mm |
| 3 μm | 120 Å | 2.1×50 mm, 2.1×100 mm, 3.0×50 mm, 3.0×100 mm, 4.6×50 mm, 4.6×100 mm, 4.6×150 mm, 4.6×250 mm |
| 1.8 μm | 120 Å | 2.1×50 mm, 2.1×100 mm, 3.0×50 mm, 3.0×100 mm, 4.6×50 mm, 4.6×100 mm, 4.6×150 mm, 4.6×250 mm |
USHD C18-AQ
Polar and hydrophilic compounds, including methods that use high-water or 100% aqueous mobile phases. Typical samples include organic acids, metabolites and water-soluble compounds.
| Particle Size | Pore Size | Standard Dimensions |
|---|---|---|
| 5 μm | 120 Å | 2.1×50 mm, 2.1×100 mm, 3.0×50 mm, 3.0×100 mm, 4.6×50 mm, 4.6×100 mm, 4.6×150 mm, 4.6×250 mm |
| 3 μm | 120 Å | 2.1×50 mm, 2.1×100 mm, 3.0×50 mm, 3.0×100 mm, 4.6×50 mm, 4.6×100 mm, 4.6×150 mm, 4.6×250 mm |
| 1.8 μm | 120 Å | 2.1×50 mm, 2.1×100 mm, 3.0×50 mm, 3.0×100 mm, 4.6×50 mm, 4.6×100 mm, 4.6×150 mm, 4.6×250 mm |
USHD C18-AR
Low-pH methods. Published pH range starts at 0.5. Used for isomer separations, peptides and mixed polar / non-polar samples.
| Particle Size | Pore Size | Standard Dimensions |
|---|---|---|
| 5 μm | 120 Å | 2.1×50 mm, 2.1×100 mm, 3.0×50 mm, 3.0×100 mm, 4.6×50 mm, 4.6×100 mm, 4.6×150 mm, 4.6×250 mm |
| 3 μm | 120 Å | 2.1×50 mm, 2.1×100 mm, 3.0×50 mm, 3.0×100 mm, 4.6×50 mm, 4.6×100 mm, 4.6×150 mm, 4.6×250 mm |
| 1.8 μm | 120 Å | 2.1×50 mm, 2.1×100 mm, 3.0×50 mm, 3.0×100 mm, 4.6×50 mm, 4.6×100 mm, 4.6×150 mm, 4.6×250 mm |
USHD C18-T
Wide pH range on ultra-pure organic-inorganic hybrid silica. Used for alkaline compounds, biological samples and complex matrices.
| Particle Size | Pore Size | Standard Dimensions |
|---|---|---|
| 5 μm | 120 Å | 2.1×50 mm, 2.1×100 mm, 3.0×50 mm, 3.0×100 mm, 4.6×50 mm, 4.6×100 mm, 4.6×150 mm, 4.6×250 mm |
| 3 μm | 120 Å | 2.1×50 mm, 2.1×100 mm, 3.0×50 mm, 3.0×100 mm, 4.6×50 mm, 4.6×100 mm, 4.6×150 mm, 4.6×250 mm |
| 1.8 μm | 120 Å | 2.1×50 mm, 2.1×100 mm, 3.0×50 mm, 3.0×100 mm, 4.6×50 mm, 4.6×100 mm, 4.6×150 mm, 4.6×250 mm |
Applications
Match the phase to the mobile phase and the sample, not to an industry label alone.
USHD C18-Pro
General reversed-phase work where a lower carbon load and 150 Å pore are preferred: pharmaceuticals, traditional Chinese medicine, food and environmental samples.
USHD C18
Higher carbon load for stronger retention and selectivity on routine reversed-phase methods.
USHD C18-AQ
Polar and hydrophilic compounds, including methods that use high-water or 100% aqueous mobile phases. Typical samples include organic acids, metabolites and water-soluble compounds.
USHD C18-AR
Low-pH methods. Published pH range starts at 0.5. Used for isomer separations, peptides and mixed polar / non-polar samples.
USHD C18-T
Wide pH range on ultra-pure organic-inorganic hybrid silica. Used for alkaline compounds, biological samples and complex matrices.
Related: USHD C8 HPLC columns when a C18 method retains too strongly. All HPLC columns.
Support
Send the current column brand, dimensions and mobile phase if you want a phase recommendation before ordering.
Phase selection
We match C18-Pro, C18, C18-AQ, C18-AR or C18-T to your pH, mobile phase and analyte polarity.
Catalog confirmation
Quote requests should include phase, particle size, dimensions and quantity. We confirm the catalog number with the reply.
OEM and custom sizes
Standard dimensions are listed above. Other internal diameters and lengths can be discussed as a custom column.
FAQ
Answers from the published USHD C18 specifications.
01 Which USHD C18 phase should I start with?
For a general reversed-phase method, start with USHD C18 (17% carbon, 120 Å, pH 2–8) or USHD C18-Pro (10% carbon, 150 Å, pH 2–8). Use C18-AQ for high-water mobile phases, C18-AR when the method runs down to pH 0.5, and C18-T when the method needs pH up to 11.
02 What particle sizes and column dimensions are listed?
C18-Pro is listed at 5 μm and 3.5 μm, 150 Å. USHD C18, C18-AQ, C18-AR and C18-T are listed at 5 μm, 3 μm and 1.8 μm, 120 Å. Standard dimensions are 2.1×50, 2.1×100, 3.0×50, 3.0×100, 4.6×50, 4.6×100, 4.6×150 and 4.6×250 mm.
03 Are these columns USP L1?
Yes. Each USHD C18 phase on this page is classified as USP L1, octadecylsilane chemically bonded to porous silica.
04 How do I get a catalog number?
Send the phase name, particle size, pore size and column dimensions. We will confirm the catalog number, availability and price.
05 When would I choose C8 instead?
C8 (USP L7) is less hydrophobic than C18 and is used when analytes retain too strongly on C18 or when a shorter run is needed. See the USHD C8 HPLC column page.
Need a size matched to your method?
Request a USHD C18 Quote
Tell us the phase, dimensions, particle size and quantity. We will confirm the catalog number and reply with availability and pricing.
Helpful to include:
- Phase (C18-Pro, C18, C18-AQ, C18-AR, C18-T)
- Particle size and dimensions
- Mobile phase or current column brand
- Quantity and destination
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