USP L21 column: PS-DVB polymer (rigid)
Rigid spherical styrene-divinylbenzene copolymer particles of 3-30 um.
Mode: reversed-phase Typical pH range: wide, roughly 1-13 (polymer base)
Typical uses
- Reversed-phase methods needing high or low pH
- Antibiotics and basic drugs that tail on silica
- Some ion-pair methods
Common sizes (length x internal diameter, particle size)
- 250 x 4.6 mm, 5 um
- 150 x 4.6 mm, 3-5 um
Lower efficiency than silica C18; polymer can swell with some solvents.
Example columns sold as USP L21
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 |
|---|---|---|---|
| Hamilton | PRP-1 | rigid PS-DVB polymer | not stated in source |
| Waters | Styragel HR series | PS-DVB polymer (GPC) | not stated in source |
| Resonac (Shodex) | RSpak DS-613 | PS-DVB polymer | not stated in source |
| Macherey-Nagel | NUCLEOGEL RP | PS-DVB polymer | not stated in source |
| Shimadzu | Shim-pack GPC-800 series | PS-DVB polymer (GPC) | not stated in source |
| Welch Materials | Xtimate PS/DVB | PS-DVB polymer | 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 L21 packing (PS-DVB polymer (rigid)), 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 L21 designation and the stated dimensions is acceptable.
Size:
Changing length or particle size
You can keep the USP L21 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 | L13 C1 (trimethylsilane) | 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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