|
effective
pH range
|
pKa 25°C
|
buffer
|
|
1.2-2.6
|
1.97
|
maleate (pK1)
|
|
1.7-2.9
|
2.15
|
phosphate (pK1)
|
|
2.2-3.6
|
2.35
|
glycine (pK1)
|
|
2.2-6.5
|
3.13
|
citrate (pK1)
|
|
2.5-3.8
|
3.14
|
glycylglycine
(pK1)
|
|
2.7-4.2
|
3.40
|
malate (pK1)
|
|
3.0-4.5
|
3.75
|
formate
|
|
3.0-6.2
|
4.76
|
citrate (pK2)
|
|
3.2-5.2
|
4.21
|
succinate
(pK1)
|
|
3.6-5.6
|
4.76
|
acetate
|
|
3.8-5.6
|
4.87
|
propionate
|
|
4.0-6.0
|
5.13
|
malate (pK2)
|
|
4.9-5.9
|
5.23
|
pyridine
|
|
5.0-6.0
|
5.33
|
piperazine
(pK1)
|
|
5.0-7.4
|
6.27
|
cacodylate
|
|
5.5-6.5
|
5.64
|
succinate
(pK2)
|
|
5.5-6.7
|
6.10
|
MES
|
|
5.5-7.2
|
6.40
|
citrate (pK3)
|
|
5.5-7.2
|
6.24
|
maleate (pK2)
|
|
5.5-7.4
|
1.70, 6.04, 9.09
|
histidine
|
|
5.8-7.2
|
6.46
|
bis-tris
|
|
5.8-8.0
|
7.20
|
phosphate (pK2)
|
|
6.0-12.0
|
9.50
|
ethanolamine
|
|
6.0-7.2
|
6.59
|
ADA
|
|
6.0-8.0
|
6.35
|
carbonate (pK1)
|
|
6.1-7.5
|
6.78
|
ACES
|
|
6.1-7.5
|
6.76
|
PIPES
|
|
6.2-7.6
|
6.87
|
MOPSO
|
|
6.2-7.8
|
6.95
|
imidazole
|
|
6.3-9.5
|
6.80, 9.00
|
BIS-TRIS propane
|
|
6.4-7.8
|
7.09
|
BES
|
|
6.5-7.9
|
7.14
|
MOPS
|
|
6.8-8.2
|
7.48
|
HEPES
|
|
6.8-8.2
|
7.40
|
TES
|
|
6.9-8.3
|
7.60
|
MOBS
|
|
7.0-8.2
|
7.52
|
DIPSO
|
|
7.0-8.2
|
7.61
|
TAPSO
|
|
7.0-8.3
|
7.76
|
triethanolamine (TEA)
|
|
7.0-9.0
|
0.91, 2.10, 6.70, 9.32
|
pyrophosphate
|
|
7.1-8.5
|
7.85
|
HEPPSO
|
|
7.2-8.5
|
7.78
|
POPSO
|
|
7.4-8.8
|
8.05
|
tricine
|
|
7.5-10.0
|
8.10
|
hydrazine
|
|
7.5-8.9
|
8.25
|
glycylglycine
(pK2)
|
|
7.5-9.0
|
8.06
|
Trizma (tris)
|
|
7.6-8.6
|
8.00
|
EPPS, HEPPS
|
|
7.6-9.0
|
8.26
|
BICINE
|
|
7.6-9.0
|
8.30
|
HEPBS
|
|
7.7-9.1
|
8.40
|
TAPS
|
|
7.8-9.7
|
8.80
|
2-amino-2-methyl-1,3-propanediol (AMPD)
|
|
8.2-9.6
|
8.90
|
TABS
|
|
8.3-9.7
|
9.00
|
AMPSO
|
|
8.4-9.6
|
9.06
|
taurine (AES)
|
|
8.5-10.2
|
9.23, 12.74, 13.80
|
borate
|
|
8.6-10.0
|
9.50
|
CHES
|
|
8.7-10.4
|
9.69
|
2-amino-2-methyl-1-propanol (AMP)
|
|
8.8-10.6
|
9.78
|
glycine (pK2)
|
|
8.8-9.9
|
9.25
|
ammonium hydroxide
|
|
8.9-10.3
|
9.60
|
CAPSO
|
|
9.5-11.1
|
10.33
|
carbonate (pK2)
|
|
9.5-11.5
|
10.66
|
methylamine
|
|
9.5-9.8
|
9.73
|
piperazine
(pK2)
|
|
9.7-11.1
|
10.40
|
CAPS
|
|
|
12.33
|
phosphate (pK3)
|
|
10.0-11.4
|
10.70
|
CABS
|
|
10.5-12.0
|
11.12
|
piperidine
|
|
|
buffer
|
pKa 25°C
|
effective
pH range
|
|
ACES
|
6.78
|
6.1-7.5
|
|
acetate
|
4.76
|
3.6-5.6
|
|
ADA
|
6.59
|
6.0-7.2
|
|
ammonium hydroxide
|
9.25
|
8.8-9.9
|
|
AMP (2-amino-2-methyl-1-propanol)
|
9.69
|
8.7-10.4
|
|
AMPD (2-amino-2-methyl-1,3-propanediol)
|
8.80
|
7.8-9.7
|
|
AMPSO
|
9.00
|
8.3-9.7
|
|
BES
|
7.09
|
6.4-7.8
|
|
BICINE
|
8.26
|
7.6-9.0
|
|
bis-tris
|
6.46
|
5.8-7.2
|
|
BIS-TRIS propane
|
6.80, 9.00
|
6.3-9.5
|
|
borate
|
9.23, 12.74, 13.80
|
8.5-10.2
|
|
CABS
|
10.70
|
10.0-11.4
|
|
cacodylate
|
6.27
|
5.0-7.4
|
|
CAPS
|
10.40
|
9.7-11.1
|
|
CAPSO
|
9.60
|
8.9-10.3
|
|
carbonate (pK1)
|
6.35
|
6.0-8.0
|
|
carbonate (pK2)
|
10.33
|
9.5-11.1
|
|
CHES
|
9.50
|
8.6-10.0
|
|
citrate (pK1)
|
3.13
|
2.2-6.5
|
|
citrate (pK2)
|
4.76
|
3.0-6.2
|
|
citrate (pK3)
|
6.40
|
5.5-7.2
|
|
DIPSO
|
7.52
|
7.0-8.2
|
|
EPPS, HEPPS
|
8.00
|
7.6-8.6
|
|
ethanolamine
|
9.50
|
6.0-12.0
|
|
formate
|
3.75
|
3.0-4.5
|
|
glycine (pK1)
|
2.35
|
2.2-3.6
|
|
glycine (pK2)
|
9.78
|
8.8-10.6
|
|
glycylglycine
(pK1)
|
3.14
|
2.5-3.8
|
|
glycylglycine
(pK2)
|
8.25
|
7.5-8.9
|
|
HEPBS
|
8.30
|
7.6-9.0
|
|
HEPES
|
7.48
|
6.8-8.2
|
|
HEPPSO
|
7.85
|
7.1-8.5
|
|
histidine
|
1.70, 6.04, 9.09
|
5.5-7.4
|
|
hydrazine
|
8.10
|
7.5-10.0
|
|
imidazole
|
6.95
|
6.2-7.8
|
|
malate (pK1)
|
3.40
|
2.7-4.2
|
|
malate (pK2)
|
5.13
|
4.0-6.0
|
|
maleate (pK1)
|
1.97
|
1.2-2.6
|
|
maleate (pK2)
|
6.24
|
5.5-7.2
|
|
MES
|
6.10
|
5.5-6.7
|
|
methylamine
|
10.66
|
9.5-11.5
|
|
MOBS
|
7.60
|
6.9-8.3
|
|
MOPS
|
7.14
|
6.5-7.9
|
|
MOPSO
|
6.87
|
6.2-7.6
|
|
phosphate (pK1)
|
2.15
|
1.7-2.9
|
|
phosphate (pK2)
|
7.20
|
5.8-8.0
|
|
phosphate (pK3)
|
12.33
|
|
|
piperazine
(pK1)
|
5.33
|
5.0-6.0
|
|
piperazine
(pK2)
|
9.73
|
9.5-9.8
|
|
piperidine
|
11.12
|
10.5-12.0
|
|
PIPES
|
6.76
|
6.1-7.5
|
|
POPSO
|
7.78
|
7.2-8.5
|
|
propionate
|
4.87
|
3.8-5.6
|
|
pyridine
|
5.23
|
4.9-5.9
|
|
pyrophosphate
|
0.91, 2.10, 6.70, 9.32
|
7.0-9.0
|
|
succinate
(pK1)
|
4.21
|
3.2-5.2
|
|
succinate
(pK2)
|
5.64
|
5.5-6.5
|
|
TABS
|
8.90
|
8.2-9.6
|
|
TAPS
|
8.40
|
7.7-9.1
|
|
TAPSO
|
7.61
|
7.0-8.2
|
|
taurine (AES)
|
9.06
|
8.4-9.6
|
|
TES
|
7.40
|
6.8-8.2
|
|
tricine
|
8.05
|
7.4-8.8
|
|
triethanolamine (TEA)
|
7.76
|
7.0-8.3
|
|
Trizma (tris)
|
8.06
|
7.5-9.0
|
|