What's on this page?
|
Tables dealing with elution strength (  )
on silica and alumina, refractive index (ri),
UV cutoff, viscosity, the Hildebrand solubility parameter ( ), the Snyder
polarity index and boiling point (BP) of solvents are listed here. The
data is sorted on:
The Excel (version 97) file containing all data
is available for download here.
(An alternative is offered at
Reall, which displays solvent properties
like the polarity ( on
alumina), dielectric constant, dipole, boiling point, UV cutoff
(at 10%), selectivity group and viscosity (cP at 20'C).
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Hildebrand solvent scale
The Hildebrand solvent scale is a list of common solvents used in Liquid Chromatography in order of increasing energy of adsorption on
alumina. The values are
different from the values on silica gel or alumina, but the order is essentially the same.
(Hildebrand solubility values in tables below  ).
Selection of starting solvent
The starting solvent selected for a given separation can be chosen by matching the relative polarity of the solvent to that of the sample. This is done as a first approximation by selecting the solvent to match the most polar functional group on the sample molecule (e.g. alcohols for OH, amines for
NH2, etc.). From this attempt, the separation can be refined by the following procedure:
-
If the sample appears at the solvent front then the solvent is too polar to allow the adsorbent
to retard the sample. Go to a solvent higher up (lower polarity) on the scale.
-
Conversely if the sample does not appear in a reasonable time go to a solvent or solvent blend lower down (higher polarity) on the scale.
Solvent blends
Solvent blends are most useful when they are composed of pairs, which differ in adsorption energy by no more than 100%. (Example: propanol at energy 0.82 and chloroform at energy 0.40.)
Solvent gradients
Solvent gradients should be generated on the same basis of no more than doubling the energy of the starting solvent. The range is more than sufficient for most if not all
separation problems.
When changing solvents or when regenerating after a gradient, a minimum of 5-10 column volumes of the new starting solvent should flow through the system before making another sample injection.
For a estimation of your column volume, click here.
Solvent miscibility
Normally, solvents are completely miscible if they are on the same half of the
scale (from 0 to 1). In other words, all solvents on the upper half of the scale are completely miscible, or all on the bottom half are miscible with each other, and all solvents from the center half (1/4 to 3/4) are mutually miscible. There are several "universal" solvents such as tetrahydrofuran and
acetonitrile, which are miscible with almost all others except hexane and pentane. By far the most useful "rinsing, or
cleanout" solvent is iso-propanol, which is miscible with all others at all concentration
levels. A solvent miscibility table can be
found elsewhere on this site.
|
| The general separation problem |
| Change the solvent strength: In
isocratic runs, increase or decrease the modifier concentration
with a few per cent. In gradient runs, change the gradient
steepness.
Change the column temperature ±10°C. Change the pH of
the mobile phase ±0.5 pH units. |
|
 Al2O3
|
SiO2 |
solvent |
ri |
UV cutoff |
 (cP) at 20°C
|
Hildebrand solubility parameter  |
polarity index (Snyder) |
BP (°C) |
|
0.01 |
0.01 |
i-octane |
1.404 |
197-210 |
0.5 |
7 |
0.4 |
99.2 |
|
0.01 |
0.03 |
n-hexane |
1.375 |
195 |
0.313 |
7.3 |
0 |
68.9 |
|
0.04 |
0.04 |
cyclohexane |
1.427 |
200 |
0.98 |
8.2 |
0 |
80.7 |
|
0.04 |
|
n-decane |
1.412 |
210 |
0.92 |
7.8 |
0.3 |
174.1 |
|
0.18 |
0.12 |
carbon tetrachloride |
1.466 |
265 |
0.97 |
8.6 |
1.7 |
76.5 |
|
0.28 |
0.22 |
i-propyl ether |
1.368 |
220 |
0.33-0.37 |
7.3 |
2.2 |
68.3 |
|
0.29 |
0.23 |
toluene |
1.496 |
285 |
0.59 |
8.9 |
2.3 |
101.6 |
|
0.32 |
0.25 |
benzene |
1.501 |
280 |
0.65 |
9.2 |
3 |
80.1 |
|
0.36-0.4 |
0.26 |
chloroform |
1.443 |
245 |
0.57 |
9.2 |
3.4-4.4 |
61.2 |
|
0.4 |
0.32 |
dichloromethane |
1.424 |
232 |
0.44 |
9.6 |
3.4 |
40 |
|
0.42 |
0.32 |
methylene chloride |
1.424 |
233 |
0.44 |
9.7 |
3.4 |
39.8 |
|
0.45 |
0.35 |
tetrahydrofuran |
1.408 |
212-230 |
0.55 |
9.1 |
4.2 |
66 |
|
0.49 |
0.38 |
ethylene dichloride |
1.445 |
230 |
0.79 |
9.7 |
3.7 |
83.5 |
|
0.51 |
0.39 |
methyl ethyl ketone (MEK) |
1.379 |
330 |
0.43 |
9.3 |
4.5 |
80 |
|
0.56-0.58 |
0.47-0.53 |
acetone |
1.359 |
330 |
0.32 |
9.6 |
5.4 |
56.3 |
|
0.55-0.65 |
0.5 |
acetonitrile |
1.344 |
190 |
0.37 |
11.7 |
6.2 |
81.6 |
|
0.58 |
0.38-0.48 |
ethyl acetate |
1.37 |
256 |
0.46-0.47 |
9.1 |
4.3 |
77.1 |
|
0.6 |
0.46 |
methyl acetate |
1.362 |
260 |
0.37-0.45 |
9.2 |
4.4 |
56.3 |
|
0.62 |
0.41 |
dimethyl sulfoxide |
1.478 |
|
2.24 |
12.8 |
6.5 |
189 |
|
0.71 |
|
pyridine |
1.51 |
305-330 |
0.94 |
10.7 |
5.3 |
115.3 |
|
0.74 |
|
methoxyethanol, 2- |
1.401 |
220 |
1.72 |
|
5.7 |
124.6 |
|
0.82 |
|
propanol, 2- |
1.38 |
210+ |
2.35 |
|
4.3 |
82.4-117.7 |
|
0.88 |
0.68 |
ethanol |
1.361 |
205-210 |
1.2 |
12 |
5.2 |
78.3 |
|
0.95 |
0.73 |
methanol |
1.329 |
205 |
0.6 |
13.7 |
6.6 |
64.7 |
|
large |
|
acetic acid |
1.372 |
210 |
1.1-1.26 |
12.4 |
6.2 |
117.9 |
|
large |
|
water |
1.333 |
180 |
1 |
21 |
9 |
100 |
|
polarity index (Snyder) |
solvent |
ri |
UV cutoff |
(cP) at 20°C |
Hildebrand solubility parameter |
SiO2 |
Al2O3 |
BP (°C) |
|
0 |
cyclohexane |
1.427 |
200 |
0.98 |
8.2 |
0.04 |
0.04 |
80.7 |
|
0 |
n-hexane |
1.375 |
195 |
0.313 |
7.3 |
0.03 |
0.01 |
68.9 |
|
0.3 |
n-decane |
1.412 |
210 |
0.92 |
7.8 |
|
0.04 |
174.1 |
|
0.4 |
i-octane |
1.404 |
197-210 |
0.5 |
7 |
0.01 |
0.01 |
99.2 |
|
0.4 |
octane |
1.395 |
|
0.5 |
|
|
|
99.2 |
|
1.7 |
butyl ether |
|
|
0.7 |
|
|
|
142.2 |
|
1.7 |
carbon tetrachloride |
1.466 |
265 |
0.97 |
8.6 |
0.12 |
0.18 |
76.5 |
|
1.8 |
triethyl amine |
1.401 |
|
0.38 |
|
|
|
89.5 |
|
2.2 |
i-propyl ether |
1.368 |
220 |
0.33-0.37 |
7.3 |
0.22 |
0.28 |
68.3 |
|
2.3 |
toluene |
1.496 |
285 |
0.59 |
8.9 |
0.23 |
0.29 |
101.6 |
|
2.4 |
xylene, p- |
|
|
0.7 |
|
|
|
138 |
|
2.9 |
t-butyl methyl ether |
1.370 |
210 |
0.27 |
|
0.35 |
|
55.2 |
|
3 |
benzene |
1.501 |
280 |
0.65 |
9.2 |
0.25 |
0.32 |
80.1 |
|
3.3 |
benzyl ether |
|
|
5.33 |
|
|
|
288.3 |
|
3.4 |
dichloromethane |
1.424 |
232 |
0.44 |
9.6 |
0.32 |
0.4 |
40 |
|
3.4 |
methylene chloride |
1.424 |
233 |
0.44 |
9.7 |
0.32 |
0.42 |
39.8 |
|
3.4-4.4 |
chloroform |
1.443 |
245 |
0.57 |
9.2 |
0.26 |
0.36-0.4 |
61.2 |
|
3.7 |
dichloroethane |
|
|
|
|
|
|
83.4 |
|
3.7 |
ethylene dichloride |
1.445 |
230 |
0.79 |
9.7 |
0.38 |
0.49 |
83.5 |
|
3.9 |
butanol, 1- |
|
|
|
|
|
|
117.2 |
|
3.9 |
i-butyl alcohol |
|
|
3 |
|
|
|
117.7 |
|
4.2 |
tetrahydrofuran |
1.408 |
212-230 |
0.55 |
9.1 |
0.35 |
0.45 |
66 |
|
4.3 |
ethyl acetate |
1.370 |
256 |
0.46-0.47 |
9.1 |
0.38-0.48 |
0.58 |
77.1 |
|
4.3 |
propanol, 1- |
|
|
2.3 |
|
|
|
97.2 |
|
4.3 |
propanol, 2- |
1.380 |
210+ |
2.35 |
|
|
0.82 |
82.4-117.7 |
|
4.4 |
methyl acetate |
1.362 |
260 |
0.37-0.45 |
9.2 |
0.46 |
0.6 |
56.3 |
|
4.5 |
cyclohexanone |
|
|
2.24 |
|
|
|
155.7 |
|
4.5 |
methyl ethyl ketone (MEK) |
1.379 |
330 |
0.43 |
9.3 |
0.39 |
0.51 |
80 |
|
4.5 |
nitrobenzene |
|
|
2.03 |
|
|
|
210.8 |
|
4.6 |
benzonitrile |
|
|
1.22 |
|
|
|
191.1 |
|
4.8 |
dioxane, 1,4- |
|
|
|
|
|
|
101 |
|
4.8 |
dioxane, p |
|
|
1.54 |
|
|
|
101.3 |
|
5.2 |
ethanol |
1.361 |
205-210 |
1.2 |
12 |
0.68 |
0.88 |
78.3 |
|
5.3 |
nitroethane |
1.392 |
380 |
0.68 |
|
|
|
114 |
|
5.3 |
pyridine |
1.510 |
305-330 |
0.94 |
10.7 |
|
0.71 |
115.3 |
|
5.4 |
acetone |
1.359 |
330 |
0.32 |
9.6 |
0.47-0.53 |
0.56-0.58 |
56.3 |
|
5.5 |
benzyl alcohol |
|
|
5.8 |
|
|
|
205.5 |
|
5.7 |
methoxyethanol, 2- |
1.401 |
220 |
1.72 |
|
|
0.74 |
124.6 |
|
6.2 |
acetic acid |
1.372 |
210 |
1.1-1.26 |
12.4 |
|
large |
117.9 |
|
6.2 |
acetonitrile |
1.344 |
190 |
0.37 |
11.7 |
0.5 |
0.55-0.65 |
81.6 |
|
6.4 |
dimethyl formamide, N,N- |
1.431 |
268 |
0.90-0.92 |
11.5 |
|
|
153 |
|
6.5 |
dimethyl sulfoxide |
1.478 |
|
2.24 |
12.8 |
0.41 |
0.62 |
189 |
|
6.6 |
methanol |
1.329 |
205 |
0.6 |
13.7 |
0.73 |
0.95 |
64.7 |
|
7.3 |
formamide |
1.450 |
210 |
3.3-3.76 |
|
|
|
210.5 |
|
9 |
water |
1.333 |
180 |
1 |
21 |
|
large |
100 |
|
solvent |
ri |
UV cutoff |
(cP) at 20°C |
Hildebrand solubility parameter |
SiO2 |
Al2O3 |
polarity index (Snyder) |
BP (°C) |
|
acetaldehyde diethyl acetal |
1.379 |
|
|
|
|
|
|
|
|
acetaldehyde diethyl acetal |
1.379 |
|
|
|
|
|
|
|
|
acetic acid |
1.372 |
210 |
1.1-1.26 |
12.4 |
|
large |
6.2 |
117.9 |
|
acetic anhydride |
1.389 |
|
|
|
|
|
|
|
|
acetone |
1.359 |
330 |
0.32 |
9.6 |
0.47-0.53 |
0.56-0.58 |
5.4 |
56.3 |
|
acetonitrile |
1.344 |
190 |
0.37 |
11.7 |
0.5 |
0.55-0.65 |
6.2 |
81.6 |
|
benzene |
1.501 |
280 |
0.65 |
9.2 |
0.25 |
0.32 |
3 |
80.1 |
|
benzonitrile |
|
|
1.22 |
|
|
|
4.6 |
191.1 |
|
benzyl alcohol |
|
|
5.8 |
|
|
|
5.5 |
205.5 |
|
benzyl ether |
|
|
5.33 |
|
|
|
3.3 |
288.3 |
|
butanol, 1- |
|
|
|
|
|
|
3.9 |
117.2 |
|
butanol, 2- |
1.395 |
|
|
|
|
|
|
|
|
butanone, 2- |
1.377 |
|
|
|
|
|
|
|
|
butyl acetate |
1.392 |
|
|
|
|
|
|
|
|
butyl acetate, sec- |
1.387 |
|
|
|
|
|
|
|
|
butyl ether |
|
|
0.7 |
|
|
|
1.7 |
142.2 |
|
butyl ethyl ether |
1.380 |
|
|
|
|
|
|
|
|
butyl formate |
1.387 |
|
|
|
|
|
|
|
|
butylamine, 2- |
1.390 |
|
|
|
|
|
|
|
|
butyraldehyde |
1.378 |
|
|
|
|
|
|
|
|
butyric acid |
1.396 |
|
|
|
|
|
|
|
|
butyronitrile |
1.382 |
|
|
|
|
|
|
|
|
carbon tetrachloride |
1.466 |
265 |
0.97 |
8.6 |
0.12 |
0.18 |
1.7 |
76.5 |
|
chlorobutane, 2- |
1.395 |
|
|
|
|
|
|
|
|
chloroform |
1.443 |
245 |
0.57 |
9.2 |
0.26 |
0.36-0.4 |
3.4-4.4 |
61.2 |
|
chloropropane, 1- |
1.386 |
|
|
|
|
|
|
|
|
chloropropane, 2- |
1.376 |
|
|
|
|
|
|
|
|
cyclohexane |
1.427 |
200 |
0.98 |
8.2 |
0.04 |
0.04 |
0 |
80.7 |
|
cyclohexanone |
|
|
2.24 |
|
|
|
4.5 |
155.7 |
|
dichloroethane |
|
|
|
|
|
|
3.7 |
83.4 |
|
dichloromethane |
1.424 |
232 |
0.44 |
9.6 |
0.32 |
0.4 |
3.4 |
40 |
|
diethyl carbonate |
1.385 |
|
|
|
|
|
|
|
|
di-isopropylamine |
1.390 |
|
|
|
|
|
|
|
|
dimethyl formamide, N,N- |
1.431 |
268 |
0.90-0.92 |
11.5 |
|
|
6.4 |
153 |
|
dimethyl sulfoxide |
1.478 |
|
2.24 |
12.8 |
0.41 |
0.62 |
6.5 |
189 |
|
dimethylbutane, 2,2- |
1.369 |
|
|
|
|
|
|
|
|
dimethylbutane, 2,3- |
1.372 |
|
|
|
|
|
|
|
|
dimethylpentane, 2,3- |
1.389 |
|
|
|
|
|
|
|
|
dimethylpentane, 2,4- |
1.379 |
|
|
|
|
|
|
|
|
dioxane, 1,4- |
|
|
|
|
|
|
4.8 |
101 |
|
dioxane, p |
|
|
1.54 |
|
|
|
4.8 |
101.3 |
|
dodecafluoro-1-hepatanol |
1.316 |
|
|
|
|
|
|
|
|
ethanol |
1.361 |
205-210 |
1.2 |
12 |
0.68 |
0.88 |
5.2 |
78.3 |
|
ethyl acetate |
1.370 |
256 |
0.46-0.47 |
9.1 |
0.38-0.48 |
0.58 |
4.3 |
77.1 |
|
ethyl ether |
1.352 |
|
|
|
|
|
|
|
|
ethyl formate |
1.358 |
|
|
|
|
|
|
|
|
ethyl propionate |
1.382 |
|
|
|
|
|
|
|
|
ethylene dichloride |
1.445 |
230 |
0.79 |
9.7 |
0.38 |
0.49 |
3.7 |
83.5 |
|
formamide |
1.450 |
210 |
3.3-3.76 |
|
|
|
|
|
|
pyridine |
1.510 |
305-330 |
0.94 |
10.7 |
|
0.71 |
5.3 |
115.3 |
|
t-butanol |
1.385 |
|
|
|
|
|
|
|
|
t-butyl methyl ether |
1.370 |
210 |
0.27 |
|
0.35 |
|
2.9 |
55.2 |
|
tetrahydrofuran |
1.408 |
212-230 |
0.55 |
9.1 |
0.35 |
0.45 |
4.2 |
66 |
|
toluene |
1.496 |
285 |
0.59 |
8.9 |
0.23 |
0.29 |
2.3 |
101.6 |
|
triethyl amine |
1.401 |
|
0.38 |
|
|
|
1.8 |
89.5 |
|
trifluoroacetic acid |
1.283 |
|
|
|
|
|
|
|
|
trifluoroethanol |
1.290 |
|
|
|
|
|
|
|
|
trifluoropropanol |
1.381 |
|
|
|
|
|
|
|
|
trimethylbutane, 2,2,3- |
1.387 |
|
|
|
|
|
|
|
|
trimethylhexane, 2,2,5- |
1.397 |
|
|
|
|
|
|
|
|
trimethylpentane, 2,2,4- |
1.389 |
|
|
|
|
|
|
|
|
valeronitrile |
1.395 |
|
|
|
|
|
|
|
|
water |
1.333 |
180 |
1 |
21 |
|
large |
9 |
100 |
|
xylene, p- |
|
|
0.7 |
|
|
|
2.4 |
138 |
|