Biomedical Engineering Reference
In-Depth Information
Table 7.5.
pH of calibration buffers between 0 and 60 °C
Buffer
A
B
C
D
E
Te m p e r a t u r e (
◦
C)
pH
0
-
4.00
6.98
7.53
9.46
5
-
4.00
6.95
7.5
9.395
10
-
4.00
6.92
7.47
9.33
15
-
4.00
6.9
7.45
9.27
20
-
4.00
6.88
7.43
9.23
25
3.56
4.01
6.865
7.41
9.18
30
3.55
4.015
6.85
7.4
9.14
35
3.55
4.025
6.855
7.39
9.1
38
3.55
4.03
6.84
7.38
9.08
40
3.55
4.035
6.84
7.38
9.07
45
3.55
4.05
6.845
7.37
9.04
50
3.55
4.06
6.83
7.37
9.01
55
3.555
4.075
6.83
-
8.98
60
3.56
4.09
6.835
-
8.96
∆
pH
1:1
+0.052
+0.08
+0.08
+0.01
References
Beynon RJ, Easterby JS (1996) Buffer solutions. IRL Press, Oxford, p 83
Covington AK (2001) In: Lide DR (ed.) CRC Handbook of chemistry and
physics, 82nd ed. CRC Press, Boca Raton, p 8-16
Stoll VS, Blanchard JS (1990) Meth Enzymol 182:24
7.4.4 Volatile Buffers
Sometimes it is helpful to use buffers that are removed during
lyophilization. Table 7.6 presents some of these volatile buffers. It
should be mentioned that a part of buffer components are bound as
counter ions to the charged residues of proteins, i.e., the lyophilized
sample is not a completely freed form buffer compounds.
Table 7.6.
Volatile buffers
Buffer
pH range
Pyridine-formic acid
2.3 - 3.5
Trimethylamine-formic acid
3.0 - 5.0
Pyridine-acetic acid
3.0 - 6.0
Trimethylamine-hydrochloric acid
6.8 - 8.8
Ammonia-formic acid
7.0 - 8.5
Triethylamine-carbon dioxide
7.0 - 12.0
Ammonium carbonate-ammonia
8.0 - 9.5
Ammonia-hydrochloric acid
8.5 - 10.0
