Equal Solvent Strengths

What's on this page?

To convert your solvent system for a particular separation method to another, you can use 'equal solvent strength' data as given in the table below. For example, look for the capacity factor of your analyte and then find the appropriate solvent mixture.
Please use this form to notify me if you have any more data on equal solvent strength mixtures for HPLC analysis.
 

Mixtures

Equal solvent strength mixtures for reversed phase chromatography for methanol, acetonitrile and tetrahydrofuran (THF) and their capacity factor k'.

% MeOH in  H2O

% MeCN in H2O

% THF in H2O

relative k'

0

0

0

100

10

6

4

40

20

14

10

16

30

22

17

6

40

32

23

2.5

50

40

30

1

60

50

37

0.4

70

60

45

0.2

80

73

53

0.06

90

86

63

0.03

100

100

72

0.01

 

Eluotropic strength

Values represented as ranges indicate multiple sources and the "" symbol means that these are defined values.
Note that in this table not only  eluotropic strength data on silica or alumina is presented but also for  C18 !
For a more detailed list and description on how to use these data, click here.
Solvent (Al2O3) (SiOH) (C18) P
Pentane 0.00 0.00 _ 0.0
Hexane 0.00-0.01 0.00-0.01 _ 0.1
Iso-octane 0.01 0.01 _ 0.1
Cyclohexane 0.04 0.03 _ 0.2
Carbon tetrachloride 0.17-0.18 0.11 _ 1.6
l-Chlorobutane 0.26-0.30 0.20 _ 1.0
Xylene 0.26 - _ 2.5
Toluene 0.20-0.30 0.22 _ 2.4
Chlorobenzene 0.30-0.31 0.23 _ 2.7
Benzene 0.32 0.25 _ _
Ethyl ether 0.38 0.38-0.43 _ 2.8
Dichloromethane 0.36-0.42 0.32-0.32 _ 3.1
Chloroform 0.36-0.40 0.26 _ 4.1
1,2-Dichloroethane 0.44-0.49 - _ 3.5
Methyl ethyl ketone 0.51 - _ 5.7
Acetone 0.56-0.58 0.47-0.53 8.8 5.1
Dioxane 0.56-0.61 0.49-0.51 11.7 4.8
1-Pentanol 0.61 - - -
Tetrahydrofuran 0.45-0.62 0.53 3.7 4.0
Methyl t-butyl ether 0.3-0.62 0.48 - 2.5
Ethyl acetate 0.58-0.62 0.38-0.48 - 4.4
Dimethyl sulfoxide 0.62-0.75 - - 7.2
Diethylamine 0.63 - - -
Acetonitrile 0.52-0.65 0.50-0.52 3.1 5.8
1-Butanol 0.70 - - 3.9
Pyridine 0.71 - - 5.3
2-Methoxyethanol 0.74 - - 5.5
n-Propyl alcohol 0.78-0.82 - 10.1 4.0
Isopropyl alcohol 0.78-0.82 0.60 8.3 3.9
Ethanol 0.88 - 3.1 -
Methanol 0.95 0.70-0.73 1.0 5.1
Ethylene glycol 1.11 - - -
Dimethyl formamide - - 7.6 6.4
Water - - - 10.2
 
last update: augustus 11, 2007