USP L20 column: Diol
Dihydroxypropyl (diol) groups bonded to porous silica or hybrid particles of 1.5-10 um, or to a monolithic rod.
Mode: normal-phase Typical pH range: about 2-8 for classic silica; wider (about 1-12) if hybrid or specially bonded
Typical uses
- Normal-phase and HILIC separations
- Size-exclusion of proteins on diol silica
- Polar excipients
Common sizes (length x internal diameter, particle size)
- 250 x 4.6 mm, 5 um
- 150 x 4.6 mm, 5 um
Used in very different modes (NP, HILIC, SEC) depending on pore size; check the monograph details.
Example columns sold as USP L20
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 |
|---|---|---|---|
| Phenomenex | Luna HILIC | fully porous silica, diol-type bonded 3/5 um | 1.5-8 |
| YMC | YMC-Triart Diol-HILIC | fully porous organic/inorganic hybrid 1.9/3/5 um | 2-10 |
| Waters | XBridge Protein BEH SEC 200A | BEH hybrid 3.5 um (SEC) | not stated in source |
| Merck (Supelco) | LiChrospher Diol | fully porous silica | not stated in source |
| Shimadzu | Shim-pack Scepter Diol-HILIC | fully porous silica | not stated in source |
| Macherey-Nagel | NUCLEOSIL OH (Diol) | fully porous silica | not stated in source |
| Nacalai Tesque (Cosmosil) | COSMOSIL Diol-120-II (SEC) | fully porous silica | not stated in source |
| Resonac (Shodex) | PROTEIN KW-800 series (SEC) | diol-bonded silica | not stated in source |
| Welch Materials | Ultisil Diol | fully porous silica | not stated in source |
9 makers listed, so a tender written by USP code stays open to competition.
Tender wording (brand-neutral)
HPLC column with USP L20 packing (Diol), 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 L20 designation and the stated dimensions is acceptable.
Size:
Changing length or particle size
You can keep the USP L20 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
L3 Bare silica | L8 Amino (aminopropyl silane)
Not sure this is the right column? Use the step-by-step column selector.