The US Pharmacopeia (USP) is a standard source for many pharmaceutical methods. The USP specifies columns by packing material rather than by manufacturer. In most categories several different types of columns are listed which differ in particle size, particle shape, and perhaps carbon load or surface area. In these cases, the USP column specifications are quite broad and several column types meet the basic specifications. For example, an L1 specification calls for octadecyl silane chemically bonded to porous silica or ceramic micro-particles, 1.5 to 10 µm in diameter, or a monolithic rod.

Many commercially available columns meet the basic specifications and may be different particle types, including totally porous, superficially porous and monoliths. However, not all C18 columns are alike, and only a limited number of the available C18 columns from any vendor will actually perform the desired separation. For increased efficiency and resolution, we recommend spherical particles, totally porous or superficially porous from 1.5 to 3.5 µm in diameter. The USP specifically gives you the flexibility to determine the best column for your needs.

USP Designations and Agilent Columns

USP Designation USP Packing Material Column Particle Size (µm) Pore Size (Å) 
 L1 Octadecyl silane chemically bonded to porous silica or ceramic micro-particles, 1.5 to 10 µm diameter, or a monolithic silica rod MetaSil AQ C18
Microsorb 100-5 C18
OmniSpher C18
Polaris C18-A
Polaris C18-Ether
Poroshell 120 Aq-C18
Poroshell 120 EC-C18
Poroshell 120 SB-C18
Poroshell 120 HPH-C18
Poroshell 300SB-C18
Poroshell 300Extend-C18
Pursuit C18
Pursuit XRs C18
SepTech ST60 10-C18
SepTech ST150 10-C18
ZORBAX Eclipse Plus C18
ZORBAX Eclipse XDB-C18
ZORBAX Extend-C18
ZORBAX 300Extend-C18
ZORBAX ODS
ZORBAX ODS classic
ZORBAX Rx-C18
ZORBAX SB-C18
ZORBAX 300SB-C18
5
3
3, 5
3, 5, 10
3, 5
2.7
1.9, 2.7, 4
1.9, 2.7, 4
1.9, 2.7, 4
5
5
3, 5, 10
3, 5, 10
10
10
1.8, 3.5, 5
1.8, 3.5, 5, 7
1.8, 3.5, 5, 7
3.5, 5
3.5, 5, 7
5
3.5, 5
1.8, 3.5, 5, 7
1.8, 3.5, 5, 7
100
120
100, 120
180
200
120
120
120
100
300
300
200
100
60
150
95
80
80
300
70
70
80
80
300
L3 Porous silica microparticles, 1.5 to 10 µm in diameter, or a monolithic silica rod MetaSil AQ Si
Microsorb 100-5 Si
Polaris Si-A
Poroshell 120 HILIC
Pursuit XRs Si
ZORBAX Rx-Sil
ZORBAX SIL
ZORBAX HILIC Plus
5
5
3, 5, 10
1.9, 2.7, 4
3, 5, 10
3.5, 5
5
3.5
80, 120
100
180
120
100
80, 300
70
95
L4 Silica gel of controlled surface porosity bonded to a solid spherical core, 30 to 50 µm in diameter Custom order
L7 Octylsilane chemically bonded to totally porous silica particles, 1.5 to 10 µm in diameter, or a monolithic silica rod Microsorb 100-5 C8
Polaris C8-A
Polaris C8-Ether
Poroshell 120 EC-C8
Poroshell 120 SB-C8
Poroshell 120 HPH-C8
Poroshell 300 SB-C8
Pursuit C8
Pursuit XRs C8
ZORBAX C8
ZORBAX Eclipse Plus C8
ZORBAX Eclipse XDB-C8
ZORBAX Rx-C8
ZORBAX SB-C8
ZORBAX Rx-C8
ZORBAX C8
ZORBAX 300SB-C8
5
3, 5, 10
3, 5
1.9, 2.7, 4
2.7
2.7, 4
5
3, 5, 10
3, 5, 10
5
1.8, 3.5, 5
1.8, 3.5, 5, 7
1.8, 3.5, 5, 7
1.8, 3.5, 5, 7
1.8, 3.5, 5, 7
5
1.8, 3.5, 5, 7
100
180
200
120
120
100
300
200
100
70
95
80
80
80
80
70
300
L8 An essentially monomolecular layer of aminopropylsilane chemically bonded to totally porous silica gel support, 3 to 10 µm in diameter Microsorb 100-5 Amino
Polaris NH2
ZORBAX NH2
5
3, 5
5
100
180
70
L9 Irregular or spherical, totally porous silica gel having a chemically bonded, strongly acidic cation-exchange coating, 3 to 10 µm in diameter SynChropak SCX
ZORBAX SCX
ZORBAX 300 SCX
6.5
5 spherical
5
300
300
300
L10 Nitrile groups chemically bonded to porous silica particles, 3 to 10 µm in diameter Microsorb 100-5 Cyano
ZORBAX CN
ZORBAX Eclipse XDB-CN
ZORBAX SB-CN
ZORBAX 300SB-CN
5
5
3.5, 5
3.5, 5
3.5, 5, 7
100
70
80
80
300
L11 Phenyl groups chemically bonded to porous silica particles, 1.5 to 10 µm in diameter Microsorb 100-5 Phenyl
Pursuit Diphenyl
Pursuit XRs Diphenyl
ZORBAX Eclipse XDB Phenyl
ZORBAX Eclipse Plus Phenyl-Hexyl
ZORBAX Phenyl
ZORBAX SB-Phenyl

5
3, 5, 10
3, 5, 10
5

1.8, 3.5, 5
3, 5
1.8, 3.5, 5

100
200
100
70

95
80
80

L13 Trimethylsilane chemically bonded to porous silica particles, 3 to 10 µm in diameter ZORBAX TMS 5 70
L14  Silica gel having a chemically bonded, strongly basic quaternary ammonium anion-exchange coating, 5 to 10 µm in diameter IonoSpher A
SynChropak SAX
ZORBAX SAX
5
6.5
5
120
300
70 
L15 Hexyl silane chemically bonded to totally porous silica particles, 3 to 10 µm MetaSil C6
L17 Strong cation-exchange resin consisting of sulfonated cross-linked styrene-divinylbenzene copolymer in the hydrogen form, 7 to 11 µm in diameter Hi-Plex H
Bio SCX NP10

8
10

N/A
N/A
L19 Strong cation-exchange resin consisting of sulfonated cross-linked styrene-divinylbenzene copolymer in the calcium form, about 9 µm in diameter Hi-Plex Ca
Hi-Plex Ca (Duo)
8
8
N/A
N/A
L20 Dihydroxy propane groups chemically bonded to porous silica particles, 5 to 10 µm in diameter MonoChrom Diol
ProSEC 300S
3, 5
5
110 
300
L21 A rigid, spherical styrene-divinylbenzene copolymer, 5 to 10 µm in diameter PLgel
PLRP-S
5, 10
5, 8
 50, 100, 500, 103, 104, 105, 106
100, 300, 1,000, 4,000
L22  A cation-exchange resin made of porous polystyrene gel with sulfonic acid groups, about 10 µm in size Hi-Plex H 8  N/A
L25 Packing having the capacity to separate compounds with a Mol Wt MW range from 1,000 to 5,000 Da (as determined by polyethylene oxide), applied to neutral, anionic and cationic water-soluble polymers PL aquagel-OH 30 8  N/A
L26 Butyl silane chemically bonded to totally porous silica particles, 3 to 10 µm in diameter Microsorb C4 3, 5, 8, 10 300
L27 Porous silica particles, 30 to 50 µm in diameter Bondesil Si
SampliQ Bulk Silica, 25 g
40 500
L34 Strong cation-exchange resin consisting of sulfonated cross-linked styrene-divinylbenzene copolymer in the lead form, about 9 µm in diameter Hi-Plex Pb 8 N/A
L35 A zirconium-stabilizes spherical silica packing with a hydrophilic (diol-type) molecular monolayer bonded phase ZORBAX GF-250
ZORBAX GF-450
4
6
150
300
L43 Pentafluorophenyl groups chemically bonded to silica particles by a propyl spacer, 5 to 10 µm in diameter Poroshell 120 PFP
Pursuit PFP
1.9, 2.7, 4
3, 5
120
200
L45 Beta cyclodextrin bonded to porous silica particles, 5 to 10 μm in diameter ChiraDex Chiral
Poroshell 120 Chiral-CD
5
2.7

120
L50 A strong cation-exchange resin made of porous silica with sulfopropyl groups, 5 to 10 µm in diameter SynChropak SCX 5 300
L52 A strong cation-exchange resin made of porous silica with sulfopropyl groups, 5 to 10 µm in diameter IonoSpher C 5 120
L56 Propyl silane chemically bonded to totally porous silica particles, 3 to 10 μm in diameter Poroshell 300SB-C3
ZORBAX SB-C3
ZORBAX 300SB-C3
 
3.5, 5
3.5, 5
 
80
300
L57 A chiral-recognition protein, ovomucoid, chemically bonded to silica particles, about 5 µm in diameter, with a pore size of 120Å ULTRON ES-OVM 5 120
L58 Strong cation-exchange resin consisting of sulfonated cross-linked styrene-divinylbenzene copolymer in the sodium form, about 6 to 30 µm diameter Hi-Plex Na
Hi-Plex Na (Octo)
10
8
N/A
N/A
L59 Packing having the capacity to separate proteins by molecular weight over the range of 5 to 7000 kDa. The packing is spherical 1.5 - 10 μm silica or hybrid packing with a hydrophilic coating. AdvanceBio SEC
Bio SEC-3
Bio SEC-5
1.9, 2.7
3
5
120, 130, 200, 300
300
300
L60 Spherical, porous silica gel, 10 µm or less in diameter, the surface of which has been covalently modified with alkyl amide groups and end capped Bonus-RP
Poroshell 120 Bonus-RP
Polaris Amide-C18
1.8, 3.5, 5, 7
2.7
3, 5, 10
80
120
180
L63 Glycopeptide teicoplanin linked through multiple covalent bonds to a 100 Angstrom units spherical silica. Chiral-T 2.7 120
L86* A 5 μ m fused core particle with a highly polar ligand possessing 5 hydroxyl groups tethered to the silica gel outer layer HILIC-OH5 2.7 120
L88 Glycopeptide vancomycin linked through multiple covalent bonds to 100 - 200 Angstroms spherical silica. Chiral-V 2.7 120
L96* Alkyl chain, reversed-phase bonded totally or superficially porous silica designed to retain hydrophilic and other polar compounds when using highly aqueous mobile phases, including 100% aqueous, 1.5 to 10 µm. Poroshell 120 SB-Aq
ZORBAX SB-Aq
1.9, 2.7, 4
1.8, 3.5, 5
120
80
L114 Sulfobetaine graft-polymerized to totally or superficially porous silica, 1.5 to 10 µm in diameter, or a monolithic rod. Packing having densely bonded zwitterionic groups with 1:1 charge balance. Poroshell 120 HILIC-Z 2.7 100

N/A - not applicable