HPLC COLUMNS
Physical Characteristics of HPLC Columns; USP Descriptions
7
Phone: 800-356-1688 or 814-353-1300
tech
tip
ManagingHighBackpressure
High backpressure is one of themost common problems encountered inHPLC analyses. Normal
column backpressure is observed after a new column has been installed and equilibratedwith
mobile phase. Unfortunately, this pressure oftenwill increase as the column is used because
particles collect on the column inlet frit.These particles can be sample impurities, mobile phase
contaminants, ormaterials from the injector or autosampler rotor seal.
In addition to increasing backpressure, particles on the frit can cause split peaks, peak tailing,
and, eventually, over-pressure shut-down. In some circumstances, these problems can be
corrected by back-flushing the column. However, inmany cases the result is an unusable column.
Tominimize backpressure problems, all samples andmobile phase solventsmust be filtered
before use, and rotor seals should be changed on a routine basis. Alongwith these preventive
measures, it is advisable to use precolumn filters such as theTrident™ guard column protection
system. Particles build up on the inexpensive, replaceable frit in the filter, instead of on the
permanent frit at the column inlet.
Page#
USP
Code
Similar Phases
Chromatographic Properties
A pentafluorophenyl phase. Unique selectivity by interactionwith functional groups of organohalogens
or other basic analytes.
Fluophase
®
PFP, Fluosep
®
-RP Phenyl,
Curosil
™
PFP
L43
26
High purity, high surface area.
—
L3
27
Proprietary stationary phase can process up to twice asmany samples per hour, compared to a
conventional C18 phase.
Unique
— 27
High purity silica.
Unique
— 28
High purity phasewith excellent peak shape for awide range of compounds.
Good general pupose reversed phase column.
Discovery
®
C18, Symmetry
®
C18,
Hypersil
®
Gold C18, Luna
®
C18, Zorbax
®
C18,
LiChrospher
®
RP-18, Inertsil
®
ODS-2,
Develosil
®
C18
L1
32
High purity, reversed phase packing for awide range of compounds.
Luna
®
C8, Symmetry
®
C8, Hypersil
®
Gold C8 L7
33
High purity, reversed phase packing for awide range of compounds. Less retentive than C18 and C8.
Supelcosil
™
Butyl (C4), Delta-Pak
™
C4
L26
32
High purity, reversed phase packing for awide range of compounds. Less retentive than C18, C8, and C4.
Spherisorb
®
C1
L13
33
High purity, base deactivated reversed phase packing. Alternate selectivity to alkyl phases.
Platinum
™
Phenyl, Supelcosil
™
Phenyl,
Betasil
®
Phenyl
L11
33
High purity, base deactivated reversed phase packing. Alternate selectivity to alkyl phases.
Platinum
™
Amino, Develosil
®
NH2
L8
33
High purity, base deactivated packing.
—
L3
33
Silicamanufactured by Restek.
BioBasic
®
18, Symmetry
®
300 C18,
Jupiter
®
300 C18, Zorbax
®
300OSB C18,
Synchropak
®
C18, 208TP C18
L1
29
Silicamanufactured by Restek.
BioBasic
®
8, Zorbax
®
300OSB C8,
Synchropak
®
C8, 208TP C8
L7
29
Silicamanufactured by Restek.
BioBasic
®
4, Symmetry
®
300 C4,
Jupiter
®
300 C4, Synchropak
®
C4, 208TP C4
L26
30
Silicamanufactured by Restek.
Unique
L11
30
Silicamanufactured by Restek.
Unique
L43
30
Silicamanufactured by Restek.
—
L3
31
Excellent stability under extreme pH conditions.True C18 selectivity in a silica-based stationary phase.
Unique
— 10
HPLCColumnSelection
Guide
A useful chart to keepwith
your workbooks, or post on a
wall. Quickly scan important
characteristics of Restek
HPLC columns. Includes brief,
practical guidelines for
choosing stationary phase,
particle size, pore diameter,
and column dimensions. Also
includes USP designations for
each phase and lists similar
phases from other suppliers.
(lit. cat.# 59454C)
Free
Literature
