|
To view a complete list of buffers, please visit the Buffer Explorer.
Biological Buffers
Introduction
A buffer, as defined by Van Slyke [1], is "a substance which by its presence in solution increases the amount of acid or alkali that must be added to cause unit change in pH". Buffers are thus very important components in experiments designed to study biological reactions by maintaining a constant concentration of hydrogen ions within the physiological range. The pH of mammalian blood is maintained close to 7.38 by buffer systems such as
H2PO4- <=> HPO42-, CO2
<=> H2CO3,
H2CO3 <=> HCO3-,
many organic acids, organic bases and proteins. In living plants, the normal range of pH in tissues is about 4.0-6.2. It is not as narrowly defined as in mammalian tissues.
Universally applicable buffers for biochemistry must display:
- water solubility
- no interference with biological processes
- known complex-forming tendency with metal ions
- non-toxicity
- no interference with biological membranes (penetration, solubilisation, adsorption on surface etc.)
very low U.V. absorption at wavelength >260 nm
"BioChemika Ultra" Zwitterlonic (Good's) Buffers
The use of buffers based on inorganic or organic salts is limited because of the interference of buffer cations and anions with the biological reaction under study. The development and introduction of the Zwitterionic Biological Buffers by Good [2] did much to change this situation. This type of buffer displays the desired characteristics: Low interference with biological processes is due to the fact that anionic and cationic sites are present as non-interacting carboxylate or sulfonate and cationic ammonium groups. The pK and the buffer range of the zwitterionic substances lie within the physiological limits (pKa 6.15-9.55). Moreover the zwitterionic nature of these buffers makes them very water soluble, normally above the one-molar range. Physical constants of the buffer substance (pKa, D pKa/°C, solubility, pH- and UV-range) are included under the product entry in the alphabetical list.
"BioChemika Ultra" Buffer Salts and other Buffer Components
The traditional buffer components - organic and inorganic salts, acids and bases - are included in the sales programme section. Buffers based on these components are widely used in biochemical and biological research. The statements regarding the effect of anions and cations on biological systems also apply here. The paragraph Literature Specifications in the alphabetical list gives physical constants (pKa, solubility etc.)
Primary Standards
N.B.S.* Standard Buffer Substances [4]
Primary Standards
Composition and properties of the five primary standard buffers at 25°C (see notes on preparation, below).
Buffer solution
|
|
Tartrate |
Phthalate |
Phosphate
D |
Phosphate
E |
Borate |
|
| Buffer
substance |
KHC4H4O6 |
KHC8H4O4 |
KH2PO4
+
Na2HPO4 |
KH2PO4
+
Na2HPO4 |
Na2B4O7
10 H2O |
| g/l
soln. at 25 °C |
Saturated
at 25°C |
10.12 |
3.39 [b]
3.53 [c] |
1.179 [b]
4.30 [c] |
3.80 |
| Molality
(m) |
0.0341 |
0.05 |
0.025
[a] |
0.008695 [b]
0.03043 [c] |
0.01 |
| Molarity
(M) |
0.034 |
0.04958 |
0.02490
[a] |
0.008665 [b]
0.03032 [c] |
0.009971 |
| Density (g/ml) |
1.0036 |
1.0017 |
1.0028 |
1.0020 |
0.9996 |
| pH at 25°C |
3.557 |
4.008 |
6.865 |
7.413 |
9.180 |
| Dilution value, D
pH½ |
+0.049 |
+0.052 |
+0.080 |
+0.07
[d] |
+0.01 |
Buffer value, b ,
equiv./pH |
0.027 |
0.016 |
0.029 |
0.016 |
0.020 |
| Temp. coeff.,
dpH(S)/dt, units/°C |
-0.0014 |
+0.0012 |
-0.0028 |
-0.0028 |
-0.0082 |
[a] Concentration of each phosphate salt. [b] KH2PO4. [c]
Na2HPO4. [d] Calculated value.
Recommended standard values of pH(S) for primary standard buffers (+/- 0.005 at 0 - 60°C and +/-0.008 from 60-90°C).
| Buffer pH |
|
|
|
|
|
|
| Temp.
(°C) |
Tartrate |
Phthalate |
Phosphate
D |
Phosphate
E |
Borate |
|
| 0 |
|
4.003 |
6.984 |
7.534 |
9.464 |
| 5 |
|
3.999 |
6.951 |
7.500 |
9.395 |
| 10 |
|
3.998 |
6.923 |
7.472 |
9.332 |
| 15 |
|
3.999 |
6.900 |
7.448 |
9.276 |
| 20 |
|
4.002 |
6.881 |
7.429 |
9.225 |
| 25 |
3.557 |
4.008 |
6.865 |
7.413 |
9.180 |
| 30 |
3.552 |
4.015 |
6.853 |
7.400 |
9.139 |
| 35 |
3.549 |
4.024 |
6.844 |
7.389 |
9.102 |
| 38 |
3.548 |
4.030 |
6.840 |
7.384 |
9.081 |
| 40 |
3.547 |
4.035 |
6.838 |
7.380 |
9.068 |
| 45 |
3.547 |
4.047 |
6.834 |
7.373 |
9.038 |
| 50 |
3.549 |
4.060 |
6.833 |
7.367 |
9.011 |
| 55 |
3.554 |
40.75 |
6.834 |
|
8.985 |
| 60 |
3.560 |
4.091 |
6.836 |
|
8.962 |
| 70 |
3.580 |
4.126 |
6.845 |
|
8.921 |
| 80 |
3.609 |
4.164 |
6.859 |
|
8.885 |
| 90 |
3.650 |
4.205 |
6.877 |
|
8.8850 |
| 95 |
3.674 |
4.227 |
6.886 |
|
8.833 |
|
*N.B.S. National Bureau of Standards
Secondary Standards
Composition and properties of the two secondary standard buffers at 25°C.
Buffer solution
|
Tetraoxalate |
Calcium hydroxide |
| Buffer substance |
KH3(C2O4)2.
2H2O |
Ca(OH)2 |
| g/l of soln. at 25°C |
12.61 |
Saturated at 25°C |
| Molality (m) |
0.05 |
0.0203 |
| Molarity (M) |
0.04962 |
0.02025 |
| Density (g/ml) |
1.0032 |
0.9991 |
| pH at 25°C |
1.0032 |
12.454 |
| Dilution value,D pH1/2 |
1.679 |
- 0.28 |
| Buffer value,b, equiv./pH |
+ 0.186 |
0 09 |
Temp. coeff.,
dpH (S)/dt, units/°C |
0.070 |
- 0.033 |
|
Recommended standard values of pH(S) for the secondary buffer standards
Buffer pH
|
| Temp (°C) |
Tetraoxalate |
Calcium hydroxide |
| 0 |
1.666 |
13.423 |
| 5 |
1.668 |
13.207 |
| 10 |
1.670 |
13.003 |
| 15 |
1.672 |
12.810 |
| 20 |
1.675 |
12.627 |
| 25 |
1.679 |
12.454 |
| 30 |
1.683 |
12.289 |
| 35 |
1.688 |
12.133 |
| 38 |
1.691 |
12.043 |
| 40 |
1.694 |
11.984 |
| 45 |
1.700 |
11.841 |
| 50 |
1.707 |
11.705 |
| 55 |
1.715 |
11.574 |
| 60 |
1.723 |
11.449 |
| 70 |
1.743 |
|
| 80 |
1.766 |
|
| 90 |
1.792 |
|
| 95 |
1.806 |
|
|
Note. See below for remarks on drying potassium tetraoxalate dihydrate.
|
|
|
|
| Fluka Number |
Fluka Primary
N.B.S.* Standard Buffer Substances |
| 60219 |
Potassium
dihydrogen phospate |
| 60359 |
Potassium hydrogen
phthalate |
| 60366 |
Potassium hydrogen
D-tartrate |
| 71639 |
di-Sodium hydrogen
phosphate anhydrous |
| 71999 |
Sodium tetraborate
Decahydrate |
|
|
|
|
|
Fluka Secondary
N.B.S.* Standard Buffer Substances |
| 21187 |
Calcium hydroxide |
| 60589 |
Potassium
tetraoxalate Dihydrate |
|
Notes
Notes on the preparation
The primary and secondary standard buffer solutions are prepared from the standard buffer substances as indicated in the table. The standard pH [pH(S)] of the buffer solution in the temperature range 0-95°C are indicated and can be used for calibration purposes. Buffer compositions are on the molal scale. Only freshly prepared solutions should be used, as the initial buffer composition may change very rapidly. Tartrate, phthalate, and phosphates may be dried at 110°C for 1-2 hours prior to use. Potassium tetraoxalate should not be dried above 60°C, and borax should not be dried at all.
| Molality (m) |
dimension: mole per kilogram
of solvent |
| Molarity (M) |
dimension: mole per litre of
solution |
| Dilution value (DpH1/2) |
change of pH value observed by
dilution of a buffer solution with an equal volume of pure water. It is positive when pH
increases and negative when pH decreases with increasing dilution |
| Buffer value b
(equiv./pH) |
(also Buffer
capacity, Van Slyke Buffer value) b = d[B]/dpH, where d[B] is the increment (in
equivalents) of a strong base required to produce a certain pH change of the buffer
solution. Strong acids effect negative (-d[B]) increment and thus lower the pH |
| Temperature
coefficient (pH unit/°C) |
dpH(S)/dT standard change of
pH value per degree centigrade. It can be positive or negative |
General Aspects regarding Buffer Applications
With few exceptions, studies of biochemical systems require the use of a buffer in order to control the pH value. Therefore the action of the buffer is of prime importance. Factors influencing the action of buffer solutions and pH are [5, 6]:
- activity effects: concentration and electrical charge of the species involved
- salt effects: added "indifferent" electrolytes
- dilution effect: pH-variation on dilution of buffer solutions buffer capacity: added base or acid
- temperature dependence
The choice of the correct buffer for a particular biochemical system or technique depends on a number of additional factors. For example: undesired interaction of the buffer with the biopolymer, redox stability, metal ion complexing properties and purity. One way to solve the difficult problem of selecting the right buffer is to evaluate as many buffers as possible. Reviews on the use of buffers in various areas are available [7-9]. However they do not provide detailed information and a comprehensive treatise on the subject should be consulted.
Practical Aspects of Buffer Application
- Activity and salt effects have a marked influence on the pH value of a solution according to the equation
pH = pKa' + log[B]/[BH] (1)
where
pKa' = pKa + correction factor
The factors for different ionic strengths are tabulated in [5] and range from 0.015 for ionic strength I = 0.001 to 0.159 for I = 0.5.
- lonic strength is defined as in
where ci is the concentration of species i, and z is the corresponding charge. I can be calculated very easily from the experimental parameters.
Buffer capacity. The maximum buffer capacity bmax of a monovalent species is found to be at pH = pKa', the practical pK-value. bmax in the pH range 3-11 is calculated according to equation (3)
bmax = 0.576 c (3)
where c is the total concentration of the buffer substance.
Thus the useful buffer capacity lies within a pH range of pKa± 1 unit. If more than 50% of the maximum buffer capacity must be realized the
corresponding range is only pKa' + 0.75 units.
The Practical Buffer Range
b, the buffer capacity, is defined as given in (4)
b =d [B] (4)
dpH
where [B] is the amount of base added to the buffer component BH. The buffer capacity of a mixed weak acid-base buffer system is greater, the closer the individual pKa values lie.
b values of a mixture of buffers are additive.
From equation (5) it is possible to calculate the molar ratio [basic species]/[acidic species] which leads to a desired pH within the practical buffer range, pKa± 1 unit.
pH = pK + log[basic species] (5)
[acid species]
From the diagram on page ...
[B]/[BH] - pH - % buffer capacity can quickly be estimated.
Temperature effects on the pH of a given solution may be considerable. TRIS has a pKa of 8.55 at 0°, 8.06 at 25° and 7.22 at 37° (mean dpH/dT-0.03 pH units/°C). Salt buffers, such as the Primary Standards show dpH/dT of about 0.002 pH-units/°C. The change can be either positive or negative.
Dilution effects depend mainly on the charge of the buffer species; dilution of a 0.1 M HA/A- buffer system (total concentration) with an equal volume of water results in a pH-value change of 0.024 units, whereby the pH is lowered in the case of basic buffers and increased when acidic ones are diluted. The pH variation of HA-/A2- buffer systems are increasod by a factor of approximately three.
Use of diagram: Determine from experimental parameters the molar concentration ratio of basic and acidic speries in the buffer system.
(1 to 10)
10 1
Read the pH of the Solution from the upper diagram of pH deviation and from the lower diagram the % of maximum buffer capacity (% bmax).
pKa Value and Buffer Range of important Biological Buffers
sorted by buffer range
sorted alphabetically
pKa Value and Buffer Range of important Biological Buffers sorted by buffer range
effective pH range |
pKa 25°C |
buffer |
|
1.2-2.6 |
1.97 |
maleate (pK1) |
1.7-2.9 |
2.15 |
phosphate (pK1) |
10.0-11.4 |
10.70 |
CABS |
10.5-12.0 |
11.12 |
piperidine |
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) |
pKa Value and Buffer Range of important Biological Buffers sorted alphabetically
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 |
List of Common Buffers
A-B C-D E-H I-O P-R S T-Z
| Catalog No. |
Name |
see |
|
|
A-B |
|
| 00194 |
ACES |
|
| 00194 |
N-(2-Acetamido)-2-aminoethanesulfonic acid |
|
|
N-(2-Acetamido)iminodiacetic acid |
ADA |
|
Acetic acid magnesium salt |
Magnesium acetate |
|
Acetic acid sodium salt |
Sodium acetate |
| 45725 |
Acetic acid for luminescence |
|
| 45726 |
Acetic acid |
|
| 00307 |
ADA |
|
|
Aminoacetic acid |
Glycine |
|
Aminoethanoic acid |
Glycine |
|
2-Amino-2-(hydroxymethyl)-1,3-propanediol |
Trizma® base |
|
beta-Aminoisobutyl alcohol, AMP |
2-Amino-2-methyl-1-propanol |
| 08578 |
2-Amino-2-methyl-1-propanol |
|
| 08569 |
2-Amino-2-methyl-1,3-propanediol |
|
|
Ammediol |
2-Amino-2-methyl-1,3-propanediol |
|
Ammonium dihydrogen phosphate |
Ammonium phosphate monobasic |
|
Ammonium sodium hydrogen phosphate |
Ammonium sodium phosphate dibasic tetrahydrate |
| 09681 |
Ammonium acetate for luminescence |
|
| 09830 |
Ammonium bicarbonate |
|
| 09833 |
Ammonium citrate dibasic |
|
| 09735 |
Ammonium formate |
|
|
Ammonium hydrogen carbonate |
Ammonium bicarbonate |
| 09898 |
Ammonium oxalate monohydrate |
|
| 09839 |
Ammonium phosphate dibasic |
|
| 09709 |
Ammonium phosphate monobasic |
|
|
Mono-ammonium phosphate |
Ammonium phosphate monobasic |
|
prim-Ammonium phosphate |
Ammonium phosphate monobasic |
| 71284 |
Ammonium sodium phosphate dibasic tetrahydrate |
|
| 09985 |
Ammonium tartrate dibasic |
|
|
AMP |
2-Amino-2-methyl-1-propanol |
|
AMPD |
2-Amino-2-methyl-1,3-propanediol |
|
Barbitone |
Sodium 5,5-diethylbarbiturate |
| 14853 |
BES for molecular biology |
|
| 14854 |
BES |
|
| 14280 |
BES buffered saline for molecular biology |
|
| 14871 |
BICINE |
|
|
Bis(2-hydroxyethyl)amine, 2,2'-Iminodiethanol |
Diethanolamine |
|
N,N-Bis(2-hydroxyethyl)-2-aminoethanesulfonic acid |
BES |
|
2-Bis(2-hydroxyethyl)amino-2-(hydroxymethyl)-1,3-propanediol |
BIS-TRIS |
|
Bis(2-hydroxyethyl)amino-tris(hydroxymethyl)methane |
BIS-TRIS |
|
N,N-Bis(2-hydroxyethyl)glycine |
BICINE |
|
N,N-Bis(2-hydroxyethyl)taurine |
BES |
|
2,2-Bis(hydroxymethyl)-2,2',2''-nitrilotriethanol |
BIS-TRIS |
| |
BIS-TRIS |
|
|
Borax decahydrate |
Sodium tetraborate |
| 15662 |
Boric acid for luminescence |
|
| 15663 |
Boric acid for molecular biology |
|
| 15665 |
Boric acid |
|
|
Buffer solution 1 M pH 7.0 (volatile) |
Triethylammonium acetate buffer |
| Catalog No. |
Name |
see |
|
| |
C-D |
|
| 21056 |
Calcium acetate hydrate |
|
| 21061 |
Calcium carbonate |
|
| 21118 |
Calcium citrate tribasic tetrahydrate |
|
| 21134 |
Calcium formate |
|
| 29337 |
CAPS |
|
|
N-(Carbamoylmethyl)-2-aminoethanesulfonic acid |
ACES |
|
2-(Carbamoylmethylamino)ethanesulfonic acid |
ACES |
|
N-(Carbamoylmethyl)iminodiacetic acid |
ADA |
|
N-(Carbamoylmethyl)taurine |
ACES |
| |
CHES |
|
|
Citric acid |
Ammonium citrate dibasic |
|
Citric acid calcium salt |
Calcium citrate tribasic tetrahydrate |
|
Citric acid magnesium salt |
Magnesium citrate tribasic |
|
Citric acid monopotassium salt |
Potassium citrate |
|
Citric acid monosodium salt |
Sodium citrate monobasic |
|
Citric acid trilithium salt |
Lithium citrate tribasic |
|
Citric acid trisodium salt |
'Sodium citrate tribasic |
| 27485 |
Citric acid for luminescence |
|
| 27487 |
Citric acid |
|
|
2-(Cyclohexylamino)ethanesulfonic acid |
CHES |
|
3-(Cyclohexylamino)-1-propanesulfonic acid |
CAPS |
|
Diammonium hydrogen citrate |
Ammonium citrate dibasic |
|
Diammonium tartrate |
Ammonium tartrate dibasic |
|
Diammonium hydrogen phosphate |
Ammonium phosphate dibasic |
|
di-Ammonium hydrogen phosphate (sec) |
Ammonium phosphate dibasic |
|
1,4-Diazacyclohexane |
Piperazine |
|
1,3-Diaza-2,4-cyclopentadiene |
Imidazole |
| |
Diethanolamine |
|
|
5,5-Diethylbarbituric acid sodium salt |
Sodium 5,5-diethylbarbiturate |
|
Diethylenediamine |
Piperazine |
|
Diglycine |
Gly-Gly |
|
D-2,3-Dihydroxybutanedioic acid monopotassium salt |
Potassium D-tartrate monobasic |
|
Dipotassium hydrogen phosphate |
Potassium phosphate dibasic |
|
Dipotassium phosphate |
Potassium phosphate dibasic |
|
Disodium dihydrogen pyrophosphate |
Sodium pyrophosphate dibasic |
|
Disodium ethylenediaminetetraacetate dihydrate |
Ethylenediaminetetraacetic acid disodium salt dihydrate |
|
Disodium hydrogen phosphate |
Sodium phosphate dibasic |
|
Disodium phosphate |
Sodium phosphate dibasic |
|
Disodium pyrophosphate |
Sodium pyrophosphate dibasic |
|
Disodium tartrate dihydrate |
Sodium tartrate dibasic |
|
Di(tris[hydroxymethyl]aminomethane) carbonate |
Trizma® carbonate |
| Catalog No. |
Name |
see |
|
|
E-H |
|
|
Edetate disodium salt dihydrate |
Ethylenediaminetetraacetic acid disodium salt dihydrate |
| |
EPPS |
|
|
Ethanedioic acid |
Oxalic acid dihydrate |
|
Ethanedioic acid |
Potassium oxalate |
|
Ethanedioic acid sodium salt |
Sodium oxalate |
| |
Ethylenediaminetetraacetic acid disodium salt dihydrate for molecular biology |
|
|
Formic acid ammonium salt |
Ammonium formate |
|
Formic acid calcium salt |
Calcium formate |
|
Formic acid potassium salt |
Potassium formate |
| 50046 |
Glycine for molecular biology |
|
| 50049 |
Glycine |
|
| 50056 |
Glycine for luminescence |
|
|
Glycocoll |
Glycine |
|
Glycyl-glycine |
Gly-Gly |
|
Glycyl-glycyl-glycine |
Gly-Gly-Gly |
| 50199 |
Gly-Gly |
|
|
