Merck Millipore

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Columns for USP Specifications

Columns for USP Specifications

Merck offers a comprehensive range of high-quality HPLC columns. Among these are a wide selection of columns that meet USP (United States Pharmacopoeia) specifications. The L nomenclature was introduced by the USP to designate column types for high-performance liquid chromatography. To help you select the appropriate HPLC column for your application, the table below describes various L columns as well as the corresponding HPLC columns available from Merck.

USP	Description	Columns
L1	Octadecly silane (ODS or C18) chemically bonded to porous silica or ceramic particles, 1.5 to 10 µm in diameter	Chromolith® RP-18 Endcapped LiChrosorb® RP-18 (5 µm) LiChrosorb® RP-18 (10 µm) LiChrospher® RP-18 (5 µm) LiChrospher® RP-18 (10 µm) LiChrospher® RP-18 Endcapped (5 µm) LiChrospher® RP-18 Endcapped (10 µm) Purospher® RP-18 (5 µm) Purospher® RP-18 Endcapped (5 µm) Purospher® STAR RP-18 Endcapped (3 µm) Purospher® STAR RP-18 Endcapped (5 µm) Superspher® RP-18 Endcapped (4 µm) Superspher® RP-18 (4 µm)
L3	Porous silica particles, 1.5 to 10 µm in diameter	Chromolith® Si LiChrosorb® Si 60 (5 µm) LiChrospher® Si 100 LiChrospher® Si 60 (10 µm) LiChrospher® Si 60 (5 µm) Purospher® STAR Si (5 µm) Superspher® Si 60 (4 µm)
L7	Octyl silane (C8) chemically bonded to porous silica particles, 1.5 to 10 µm in diameter	Chromolith® RP-8 Endcapped LiChrosorb® RP-8 (5 µm) LiChrosorb® RP-8 (10 µm) LiChrospher® RP-8 (5 µm) LiChrospher® RP-8 (10 µm) LiChrospher® RP-8 endcapped (5 µm) LiChrospher® RP-Select B (5 µm) LiChrospher® RP-Select B (10 µm) Purospher® STAR RP-8 Endcapped (3 µm) Purospher® STAR RP-8 Endcapped (5 µm) Superspher® 60 RP-8 (4 µm) Superspher® 60 RP-8 Endcapped (4 µm) Superspher® 60 RP-Select B (4 µm)
L8	An essentially monomolecular layer of aminopropylsilane (NH2) chemically bonded to totally porous silica gel support, 3 to 10 µm in diameter	LiChrospher® NH2 (10 µm) Purospher® STAR NH2 (5 µm)
L10	Nitrile groups (CN) chemically bonded to porous silica particles, 3 to 10 µm in diameter	LiChrospher® CN (10 µm) LiChrospher® CN (5 µm)
L20	Dihydroxypropane groups chemically bonded to porous silica particles, 3 to 10 µm in diameter	LiChrospher® Diol (5 µm) LiChrosorb® Diol (5 µm)
L29	Gamma alumina, reversed-phase, low carbon percentage by weight alumina-based polybutadiene spherical particles, 5 µm in diameter with a pore diameter of 80Å	Aluspher® RP-select B
L45	Beta cyclodextrin bonded to porous silica particles, 5 to 10 µm in diameter	ChiraDex® (5 µm)