USP L13 column: C1 (trimethylsilane)
Trimethylsilyl (C1) groups bonded to porous silica of 3-10 um.
Mode: reversed-phase Typical pH range: about 2-8 (silica base)
Typical uses
- Weak reversed-phase retention for very hydrophobic compounds
- A few older monograph assays
Common sizes (length x internal diameter, particle size)
- 250 x 4.6 mm, 5 um
- 150 x 4.6 mm, 3-5 um
Few current commercial products; phase is hydrolytically less stable than longer chains.
Example columns sold as USP L13
From the makers' own USP code lists and product pages, checked October 2026. Examples only, not an endorsement. Columns with the same code can still differ in selectivity; if the monograph names a column in its notes, start with that one.
| Maker | Product family | Particle | pH range |
|---|---|---|---|
| Merck (Supelco) | SUPELCOSIL LC-1 | fully porous silica | not stated in source |
| Waters | Spherisorb C1 | fully porous silica 3/5/10 um | not stated in source |
| Restek | Ultra C1 | fully porous silica 3/5 um | 2.5-8 |
| Shimadzu | Shim-pack CLC-TMS | fully porous silica | not stated in source |
| Nacalai Tesque (Cosmosil) | COSMOSIL TMS-MS | fully porous silica | not stated in source |
| Welch Materials | Ultisil XB-C1 | fully porous silica | not stated in source |
6 makers listed, so a tender written by USP code stays open to competition.
Tender wording (brand-neutral)
HPLC column with USP L13 packing (C1 (trimethylsilane)), 250 x 4.6 mm, 5 um (length x internal diameter, particle size); stainless-steel or equivalent hardware with standard fittings; recommended pH and temperature range to be stated by the bidder; each column supplied with its certificate of analysis and test chromatogram, batch/lot number and serial number; shelf life not less than 2 years from delivery; any make meeting the USP L13 designation and the stated dimensions is acceptable.
Size:
Changing length or particle size
You can keep the USP L13 packing and use a different length, particle size or diameter within the harmonized USP 621 limits. Check your columns with the calculator.
Related column types
L1 C18 (octadecyl silane) | L7 C8 (octyl silane) | L10 Cyano (CN, nitrile) | L11 Phenyl | L21 PS-DVB polymer (rigid) | L26 C4 (butyl silane) | L29 Polybutadiene-coated alumina (RP) | L43 PFP (pentafluorophenyl) | L60 Polar-embedded alkyl amide, endcapped | L62 C30 | L67 Polymer C18 (vinyl alcohol copolymer) | L68 Alkyl amide, not endcapped
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