800-356-1688or 814-353-1300
149
HPLCCOLUMNS
Column Selection
Multiply units in the left-most column by the conversion factors listed in the columns to the right.
e.g.,
10 psi x 0.068= 0.68atm
10 bar x 29.5300= 295.300 inches Hg
HPLCPumpPressureConversionTable
Pressure
psi
atm
kg/cm
2
torr
kPa
bar
inchesHg
1 psi= 1
0.068
0.0703
51.713
6.8948
0.06895
2.0359
1 atm=
14.696
1
1.0332
760
101.32
1.0133
29.921
1 kg/cm
2
=
14.223
0.967
1
735.5
98.06
0.9806
28.958
1 torr=
0.0193
0.00132
0.00136
1
0.1330
0.00133
0.0394
1 kPa=
0.1450
0.00987
0.0102
7.52
1
0.0100
0.2962
1 bar=
14.5038
0.9869
1.0197
751.88
100
1
29.5300
1 inHg=
0.49612
0.0334
0.0345
25.400
3.376
0.03376
1
Figure3
Restek stationaryphasesand recommendeduses.
AlkylPhases
• General purpose reversedphasecolumns relyondispersive
interaction to separatemolecules.
• Elutionorder ishydrophilic tohydrophobic; increasedchain
length increases retention.
ModifiedAlkylPhases
• Alkyl phaseswithmodifiedbondingchemistry to increasepolarity.
• Columnsarecompatiblewith100%aqueousmobilephases.
• Relyondispersive interactionwithadditional hydrogenbonding.
• Aqueous columns showbalanced retentionandareagreat
startingpoint formethoddevelopment.
• Polar embedded IBDcolumnsprovidegoodpeak symmetry for
basesandofferorthogonal selectivity toaC18.
• IBDphasesarecapableofmixedmodemechanismsandcan
operate inboth reversedphaseandHILICmodes.
PhenylPhases
• Phenyl columns relyondispersiveandpi-pi (
π
-
π
) interactions.
• Enhanced retentionand selectivityare seenwitharomatic,
conjugatedmolecules, andcompounds containingelectron
withdrawing ring substituents.
• Biphenyl andAromaxcolumns showmore interactionand
greater aromatic retentionand selectivity, relative to
conventional phenyl andphenyl-hexyl phases.
PolarPhases
• Polarphases relyonaromaticanddipole interactions.
• CyanoandPFPPropyl phases show increased retention for
aromaticcompoundsandchargedbases.
• PFPPropyl phasesarecommonlyused for increased retention
of ionicandbasiccompounds.
• Aminocolumnsarecommonlyused for theanalysisof saccharides.
• Silicacolumnsareused fornormal phaseandHILIC separations.
Si
CH
3
CH
3
O
C8
Si
CH
3
CH
3
O
C18
Si
CH
3
CH
3
O
C4
Si
CH
3
CH
3
O
C1
NonPolarRetention
Phenyl
Aromax
Si
CH
3
CH
3
O
Si
CH
3
Proprietary
CH
3
O
Biphenyl
Si
CH
3
CH
3
O
AromaticRetention
AqueousC18
Si
OO
P
IBD
CH
3
CH
3
O
Si
P
AcidicRetention
PFPPropyl
Si
CH
3
CH
3
O
F
F
F
F
F
Cyano
Si
CH
3
N
C
CH
3
O
Silica
Si
OO O
OH
Amino
Si
CH
3
NH
2
CH
3
O
orthogonal selectivity toaC18
goodchoice for LC/MS
HILICcompatible
Legend
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Mar 2011
