USP L2 column: C18 on pellicular silica (30-50 um)
C18 phase bonded onto a thin porous silica layer that coats solid spherical cores; particles 30-50 um.
Mode: reversed-phase Typical pH range: about 2-8 (silica base)
Typical uses
- Guard / pre-column packing
- Older low-efficiency methods
Common sizes (length x internal diameter, particle size)
- short guard / pre-column, dry-packed 30-50 um
Old large-particle pellicular packing; rarely used for analytical columns today.
Tender wording (brand-neutral)
HPLC column with USP L2 packing (C18 on pellicular silica (30-50 um)), short guard / pre-column, dry-packed 30-50 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 L2 designation and the stated dimensions is acceptable.
Changing length or particle size
You can keep the USP L2 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) | 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)
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