ABSTRACT
390 391 392 393 Properties of Some Solvents Useful in Biochemistry and Molecular Biology<sup>a</sup>
Solvent
M.W
Freezing Point (°C)
Boiling Point (°C760)
Density (°C)b
Viscosity (mPa s)c
Log P
pKa
UV Cutoff (nm)
1
H2O
18
0
100
1.00
0.89
–
14
190
2
MeOH
32.04
−97.8
64.7
0.79
0.54
−0.77
15.3
206
3
EtOH
4607
−114
78.4
0.79
1.07
−0.31
15.9
205
4
nPrOH
60.10
−127
97.2
0.80
2.26
0.25
16.1
210
5
iPrOH
60.10
−87.9
82.3
0.79
2.04
0.05
17.1
205
6
nBuOH
74.12
−88.6
117.6
0.81
2.54
0.88
16.1
180
7
Acn
41.05
−44
81.6
0.79
0.35
−0.34
255
8
Acetone
58.08
−94.9
56.1
0.79
0.32
−0.24
265
9
HOAc
60.05
16.7
118
1.05
1.06
−0.17
4.76
255
10
EtOAc
88.10
−83.8
77.1
0.90
0.42
0.73
265
11
EG
60.07
−13
197.6
1.1
16.9
1.93 1
12
HCOOH
46.03
8.4
100.8
1.2
1.6
−0.54
13
TFA
144.2
−15.4
72.4
1.5
0.93
−0.25
0.3
14
DMSO
78.13
18.5
189
1.1
2.47
−1.35
35.1
286
15
Formamide 2
45.05
2.5
211
1.1
3.34
−1.51
275
16
DMF
73.09
−60.3
152.8
0.94
0.80
−1.01
263
17
CHCl3
119.38
−63.4
61.2
1.48
5.63
1.27
245
18
CCl4
153.83
−23
76.8
1.59
2.03
2.83
233
19
CHCl2
84.93
−95
40
1.33
0.44
1.25
233
20
Dioxane
88.11
11.8
101.2
1.03
1.18
−0.27
215
21
THF
72.16
−108.5
65
0.89
0.53
0.46
212
22
DMAc
87.12
−20
163
0.94
0.92
−0.77
268
23
n-heptane
100.2
−90.5
98.4
0.68
0.42
4.66
200
24
n-hexane
86.18
−95.4
68.7
0.66
0.33
3.90
200
25
Toluene
92.14
−94.9
110.6
0.86
0.56
2.73
284
Abbreviations: DMF, dimethyl formamide; DMSO, dimethyl sulfoxide; EG, ethylene glycol (Ethane, 1,2-diol); TFA, trifluoroacetic acid; DMAc, N,N-dimethylacetamideT value of−1.36 has also been reported for the log P for ethylene glycol.
For additional discussion of the use of formamide as a solvent for capillary zone electrophoresis, see Porras, S.P., and Kenndler, E., Formamide as solvent for capillary zone electrophoresis, Electrophoresis 25, 2946−2958, 2004.
This information has been obtained from a variety of sources. For general reference, the following references are recommended.
Pubchem https://pubchem.ncbi.nih.gov.
Weast, Robert C., Melvin J. Astle, and William H. Beyer. CRC Handbook of Chemistry and Physics, CRC Press/Taylor & Francis Group, Boca Raton, FL, 1988.
The Merck Index: An Encyclopedia of Chemicals, Drugs, and Biologicals, ed. M.J. O’Neil, Royal Society of Chemistry, Cambridge, UK, 2013 (and previous editions published by Merck and Company, Whitehouse Station, NJ).
Shugar, G.J., and Dean, J.A., The Chemists Ready Reference Handbook, McGraw-Hill, New York, 1990.
Lide, D.R., Basic Laboratory and Industrial Chemicals, CRC Press, Boca Raton, FL, 1993.
Bruno, T.J., and Svaronos, P.D.N., Handbook of Basic Tables for Chemical Analysis, CRC Press, Boca Raton, FL, 1989.
Ramis-Ramos, G., García-Álvarez_Coque, M.C., Solvent selection in liquid chromatography, in Liquid Chromatography Fundamental and Instructions, ed. S. Fanali, P.R. Haddad, C.R. Poole, P. Schoenmakers, and D. Lloyd, Chapter 10, pp. 225−249, Elsevier, Amsterdam, the Netherlands, 2013.
Seaver, C., and Sadek, P., Solvent selectoin. Part I. UV absorption characteristics, LCGC 12, 742, 1994.
Normalized to water = 1.00 g/cm3 (1 cm3 = 1 mL)
miilepascals second (mPa s); millepascals second = centipoise
Change in pH on Addition of Solvent to Several Buffers SystemsBuffer
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p w s H https://s3-euw1-ap-pe-df-pch-content-public-u.s3.eu-west-1.amazonaws.com/9781315166629/c43c6f33-ca2a-474c-bf40-97b23aff1508/content/equ_9.tif"/>
20% ACN
40% ACN
60% ACN
20% MeOH
40% MeOH
60% MeOH
80% MeOH
0.01 M acetate
3.50
3.83
4.16
4.48
3.75
4.09
4.48
4.90
4.00
4.45
4.90
5.36
4.30
4.71
5.17
5.68
5.00
5.46
5.91
6.37
5.30
5.72
6.19
6.70
0.05 M acetate
3.50
3.95
4.39
4.84
3.79
4.19
4.65
5.14
4.00
4.46
4.91
5.37
4.30
4.71
5.17
5.68
5.00
5.46
5.91
6.37
5.30
5.71
6.18
6.68
0.01 M citrate
4.00
4.31
4.62
4.94
4.31
4.75
5.24
5.78
6.00
6.40
6.79
7.19
6.38
6.89
7.49
8.13
7.50
7.90
8.30
8.69
7.87
8.38
8.96
9.59
0.05 M citrate
4.00
4.32
4.64
4.96
4.32
4.76
5.26
5.81
6.00
6.38
6.75
7.13
6.37
6.87
7.44
8.07
7.50
7.88
8.25
8.63
7.86
8.36
8.92
9.54
0.01 M phosphate
3.50
3.77
4.04
4.30
3.82
4.27
4.77
5.32
6.50
6.88
7.20
7.55
6.90
7.45
8.08
8.76
8.00
8.35
8.70
9.05
8.38
8.91
9.51
10.16
0.05 M phosphate
3.50
3.84
4.18
4.53
3.88
4.39
4.99
5.63
6.50
6.84
7.18
7.53
6.90
7.44
8.06
8.74
8.00
8.34
8.68
9.03
8.39
8.92
9.52
10.18
0.01 M NH4
8.00
7.88
7.76
7.64
7.86
7.73
7.59
7.45
10.00
9.88
9.76
9.64
9.87
9.73
9.60
9.47
0.05 M NH4
8.00
7.88
7.76
7.64
7.86
7.73
7.59
7.45
10.00
9.94
9.76
9.64
9.86
9.73
9.59
9.46
Source: Data are taken from Subirats, X., Rosés, M., and Bosch, E., On the effects of organic solvent composition on the pH of buffer HPLC mobile phases and the pK a of analytes: A review, Sep. Purif. Rev., 36, 231−255, 2007. Effect of Acetonitrile or Methanol on the p<italic>Ka</italic> of Some Organic AcidspKa
Buffer
Water
20% Acn
40% Acn
60% Acn
20% MeOH e
40% MeOH e
60% MeOH e
Formic acid a , b
3.72
3.96(3.99) c
4.40(4.54)
4.87(5.33)
–
–
–
Acetic acid d
4.74
(5.17)
(5.76)
(6.62)
5.05
5.43
5.66
Citrate (k1) d
3.16
(3.49)
(3.90)
(4.45)
3.44
3.84
4.30
Citrate (k2) d
4.79
(5.14)
(5.60)
(6.28)
6.40
7.39
7.96
Boric acid a
9.23
9.85(9.88)
10.43(10.57)
11.00(11.45)
Carbonic acid
10.35
10.82(10.85)
11.31(11.45)
11.62(12.08)
H3PO4
2.21
(2.62)
(3.11)
(3.75)
2.63
3.09
3.68
H2PO4−
7.23
(7.60)
(8.08)
(8.73)
7.55
8.04
8.75
Tris
8.08
7.94(7.97)
7.85(7.99)
7.72(8.18)
NH4
9.29
(9.21)
(9.19)
(9.34)
9.11
8.97
8.82
Subirats, X., Bosch, E., and Rosés, M., Retention of ionizable compounds on high-performance liquid chromatography XVII pH variation in mobile phases containing formic acids, piperazine, tris, boric acid and carbonate as buffering systems and acetonitrile as organic modified, J.Chromatog. A 1216, 2491−2498, 2009.
The pKa values for neutral acids increases with addition of organic solvent with a sharp increase in pH above 60−70% solvent, while cationic acids (e.g. Tris, ammonia) shows a decrease in pKa to about 80% solvent with a sharp increase in pKa at higher concentrations (Cox, B.G., Acids, bases, and salts in mixed-aqueous solvents, Org. Process Res. Dev. 19, 1800−1808, 2015).
Numbers in parentheses are value obtained with a solvent-containing reference buffer ( p S s K a https://s3-euw1-ap-pe-df-pch-content-public-u.s3.eu-west-1.amazonaws.com/9781315166629/c43c6f33-ca2a-474c-bf40-97b23aff1508/content/equ_10.tif"/> ); value without parentheses use the aqueous reference buffer ( p w s K a https://s3-euw1-ap-pe-df-pch-content-public-u.s3.eu-west-1.amazonaws.com/9781315166629/c43c6f33-ca2a-474c-bf40-97b23aff1508/content/equ_11.tif"/> ). This is IUPAC nomenclature, where the subscript indicates the media of the sample (s being solvent) while the subscript indicate the media for the reference solvent (w being water) (IUPAC Compendium of Analytical Nomenclature. Definitive Rules 1997, Blackwell, Oxford, England, 1998).
Subirats, X., Bosch, E., and Rosés, M., Retention of ionizable compounds on high-performance liquid chromatography XV. Estimation of the pH variation of aqueous buffers with the change of the acetonitrile fraction of the mobile phase, J. Chromatog. A 1059, 33−42, 2004.
Subirats, X., Bosch, E., and Rosés, M., Retention of ionizable compounds on high-performance liquid chromatography XVII. Estimation of the pH variation of aqueous buffers with the change in methanol fraction of the mobile phase, J. Chromatog. A 1138, 203−214, 2007.
Effect of Organic Solvents on the p<italic>K</italic>a of Various AcidsCompound
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p w s Ka https://s3-euw1-ap-pe-df-pch-content-public-u.s3.eu-west-1.amazonaws.com/9781315166629/c43c6f33-ca2a-474c-bf40-97b23aff1508/content/equ_13.tif"/>
MeOH a
EtOH
EG
PG
Me2SO
DMF
Dioxane
THF
GlyGly (pKa1)
3.15
3.47
3.46
3.43
3.44
3.55
3.46
3.63
3.51
HOAc
4.59
4.90
4.95
4.82
4.86
4.96
4.95
5.28
5.29
Benzoic acid b
3.98
4.53
–
–
–
4.51
4.52
4.59
4.95
Imidazole
7.13
6.88
6.88
7.02
6.92
6.72
6.58
6.79
–
HEPES (pKa1)
2.94
2.84
2.88
3.10
2.96
2.87
2.86
2.94
2.88
HEPES (pKa2)
7.54
7.46
7.47
7.66
7.52
7.46
7.38
7.51
7.45
MES
6.14
6.07
6.04
6.30
6.18
6.04
5.97
6.08
–
Tris
8.23
8.16
8.12
8.31
8.24
8.14
8.04
8.20
–
TAPS
8.46
8.45
8.43
8.54
8.48
8.37
8.32
8.52
8.43
Boric acid
9.29
9.42
9.90
8.18 c
7.98 c
10.50
10.23
10.12
–
KH2PO4
6.91
7.39
7.40
7.24
7.25
7.64
7.44
7.49
–
Source: Data are taken from Grace, S., and Dunaway-Mariano, D., Examination of the solvent perturbation technique as a method to identify enzyme catalytic groups, Biochemistry, 22, 4238−4247, 1983. Abbreviations: HOAc, acetic acid; HEPES, N-(2-hydroxyethyl)-piperazine-N′−2-ethanesulfonic acid; MES, 2-(N-morpholino)-ethanesulfonic acid; Tris, tris(hydroxymethyl)aminomethane; TAPS, 3-[[tris(hydroxymethyl)methyl]amino]propanesulfonic acid; MeOH, methanol; EtOH, ethanol; EG, ethylene glycol; PG, propylene glycol; Me2SO, dimethyl sulfoxide; DMF, dimethylformamide; THF, tetrahydrofuran.Solvent at 25%(V/V by preparation).
A more detailed study on the effect of organic solvents (Rubino, J.T., and Berryhill, W.S., Effects of solvent polarity on the acid dissociation-constants of benzoic acid, J.Pharm. Sci. 75, 182−186, 1986).
The effect of ethylene glycol and propylene glycol on boric acid reflect the complexation of polyhydroxy compounds with boric acids resulting a decrease in pH. A similar effect has been observed with monosaccharides (Shubhada, S., and Sundaram, P.V., The role of pH change caused by the addition of water-miscible organic solvents in the destabilization of an enzyme, Enzyme Microb. Technol. 17, 330−335, 1994).
Polarity of Solvents Used in Chromatography<xref ref-type="fn" rid="fntable115_2"> <sup>a</sup> </xref>Solvent
Solvent Polarity (P′) b
Solvent Polarity (P′) b , c
Solvent Polarity (P′) d
Eluuotropic Solvent Strength (Eo) e Al2O3
Solvent Polarity f ( E N T ) https://s3-euw1-ap-pe-df-pch-content-public-u.s3.eu-west-1.amazonaws.com/9781315166629/c43c6f33-ca2a-474c-bf40-97b23aff1508/content/equ_14.tif"/>
Solvation Ability (A) g
Dielectric Constant (Εr) h
1
H2O
10.2
1.00
1.00
2.00
80.1
2
MeOH
5.1
0.5
0.95
0.762
1.25
33
3
EtOH
4.3
0.4
4.4
0.654
1.11
25.3
4
nPrOH
3.9
0.4
4.1
0.617
1.08
20.8
5
iPrOH
3.9
0.4
3.9
0.82
0.546
20.2
6
nBuOH
3.9
0.4
4.1
0.586
17.8
7
Acn
5.8
0.6
5.6
0.79
0.460
1.22
36.6
8
Acetone
0.355
1.06
21.0
9
HOAc
6.0
0.6
6.1
0.228
1.06
6.2
10
EtOAc
4.4
0.4
4.2
0.58
0.221
0.79
6.1
11
EG
6.9
0.7
0.790
1.62
41.4
12
HCOOH
6.1
0.728
51.1
13
TFA
1.72
8.4
14
DMSO
7.2
0.7
7.3
0.444
47.2
15
Formamide
9.6
0.9
0.775
1.65
111
16
DMF
6.4
0.6
6.3
0.386
1.23
38.3
17
CHCl3
4.1
0.4
4.3
0.40
0.259
1.15
4.7
18
CCl4
1.6
0.2
1.6
0.18
0.052
0.43
2.2
19
CHCl2
3.1.
0.3
4.3
0.42
0.309
1.13
8.9
20
Dioxane
4.8
5.3
0.63
0.164
0.86
2.2
21
THF
4.0
4.3
0.207
0.84
7.5
22
DMAc
6.5
6.5
38.9
23
n-heptane
1.9
24
n-hexane
0.1
−0.14
1.9
25
Toluene
2.4
2.7
2.4
Abbreviations: DMF, dimethyl formamide; DMSO, dimethyl sulfoxide; EG, ethylene glycol (Ethane, 1,2-diol); TFA, trifluoroacetic acid; DMAc, N,N-dimethylacetamideThis information has been obtained from a variety of sources. For general reference, the following references are recommended.
Pubchem, https://pubchem.ncbi.nih.gov.
CRC Handbook of Chemistry and Physics, CRC Press/Taylor & Francis Group, Boca Raton, FL.
O’Neil, M.J. et al., The Merck Index: An Encyclopedia of Chemicals, Drugs, and Biologicals, ed. Royal Society of Chemistry, Cambridge, UK, 2013. (and previous editions published by Merck and Company, Whitehouse Station, NJ.)
Shugar, G.J., and Dean, J.A., The Chemists Ready Reference Handbook, McGraw-Hill, New York, 1990.
Lide, D.R., Basic Laboratory and Industrial Chemicals, CRC Press, Boca Raton, FL, 1993.
Bruno, T.J., and Svaronos, P.D.N., Handbook of Basic Tables for Chemical Analysis, CRC Press, Boca Raton, FL, 1989.
Ramis-Ramos, G., García-Álvarez_Coque, M.C., Solvent selection in liquid chromatography, in Liquid Chromatography Fundamental and Instructions, ed. S. Fanali, P.R. Haddad, C.R. Poole, P. Schoenmakers, and D. Lloyd, Chapter 10, pp. 225−249, Elsevier, Amsterdam, Netherlands, 2013.
Seaver, C., and Sadek, P., Solvent selectoin. Part I. UV absorption characteristics, LCGC 12, 742, 1994.
Welch, J., Brkovic, T., Schafer, W., and Gong, X., Performance to burn? Re-evaluating the choice of acetonitrile as the platform solvent for analytical HPLC, Green Chem. 11, 1232−1238, 2009.
Solvent polarity (P′) as defined by L.R. Snyder (Snyder, L.R., Classification of the solvent properties of common liquids, J. Chromatog. Sci. 16, 223−234, 1978). P′ is a global estimation of solvent strength (polarity) including acidity, basicity, and dipolar characteristics.
Normalized to water = 1; not taken to more significant figures than original data.
Solvent polarity (P′) slightly. (Modified Rutan, S.C., Carr, P.W., Cheung, W.J., et al., J. Chromatog. A., 463, 21−37, 1989.)
Eluotropic is a measure of the adsorption interaction of a solvent with a specific stationary phase. In this example, the stationary phase is a normal phase thin layer (planar) chromatography. (From Gocan, S., Eluotropic series of solvents for TLC, in Encyclopedia of Chromatography, 3rd edn., ed. J.Cazes, pp. 730−735, CRC Press/Taylor & Francis Group, Boca Raton, FL, 2010.)
E T N https://s3-euw1-ap-pe-df-pch-content-public-u.s3.eu-west-1.amazonaws.com/9781315166629/c43c6f33-ca2a-474c-bf40-97b23aff1508/content/equ_15.tif"/> is ET (30) normalized to water = 1. ET(30) is an empirical scale of solvent polarity. (From Reichardt, C., Pure Appl. Chem., 76, 19093−1919, 2004.) Data shown are taken. (From Reichardt, C., Chem. Rev. 94, 2319−2358, 1994.) EtT (30) is the molar electronic transition energy of pyridinium N-phenolate betaine dye; E T N https://s3-euw1-ap-pe-df-pch-content-public-u.s3.eu-west-1.amazonaws.com/9781315166629/c43c6f33-ca2a-474c-bf40-97b23aff1508/content/equ_16.tif"/> is obtained from the normalization of ET(30) use water as the most polar solvent and tetramethylsilane as the most nonpolar solvent. Units of ET(30) are kcal mol−1 while E T N https://s3-euw1-ap-pe-df-pch-content-public-u.s3.eu-west-1.amazonaws.com/9781315166629/c43c6f33-ca2a-474c-bf40-97b23aff1508/content/equ_17.tif"/> is dimensionless.
A measure of solvation—a combination of anion-solvating ability and cation-solvating ability considered a measure of solvent polarity. (Form Reichardt, C., and Welton, T., Solvents and Solvent Effects in Organic Chemistry, 4th edn., Wiley-VCH, Weinheim, NJ, 2011.)
Also referred to as permittivity; shown here is the relative permittivity, which is the ratio of actual permittivity to permittivity in a vacuum.
