Frans_M_Everaerts_Isotachophoresis_378342.pdf

AMINO ACIDS
TABLE 13.6
DETERMINATION OF pK VALUES IN AQUEOUS PROPIONALDEHYDE SYSTEMS
Amino
acid
L-His
L-G~U*
L-AS~*
L-Ile
L-Leu
L-Val
L-Phe
DL-Ala
L-Met
L-Ser
L-Thr
3-L-Hyp
L-Trp
L-Tyr
GlY
L-Arg
L-Lys
*PK~ value.
~
Propionaldehyde concentration (mole%)
0.0 2.5 4.0 8.0
9.18
9.47
9.82
9.758
9.744
9.719
9.24
9.866
9.21
9.15
9.73
9.39
10.07
9.778
12.48
10.53
7.81
8.53
8.87
8.38
8.83
8.57
8.17
9.03
8.10
7.60
7.28
9.36
8.50
8.95
7.62
8.42
7.70
8.47
8.58
8.33
8.41
8.45
7.90
8.50
7.90
7.35
7.23
8.95
8.24
8.05
8.31
7.22
8.20
321
7.93
8.38
8.50
8.15
8.26
8.20
7.88
8.37
7.90
6.35
6.15
8.10
8.00
8.17
7.98
specified in Table 13.7 are given. Table 13.8 shows that the analysis can be performed at a
relatively low pH. By this means, the disturbance due to the carbonate (hydrogen
carbonate) is prevented, although in its place a disturbance due to propionic acid has to
be dealt with.
For the operational system specified in Table 13.7, the possibility of the formation of
TABLE 13.7
OPERATIONAL SYSTEM AT pH ABOUT 7.5 SUITABLE FOR ANIONIC SEPARATIONS IN
AQUEOUS PROPANAL' SOLUTIONS
Solvent:
H, 0 + 3% C, H, CHO.
Electric current kA): < 50.
Electrolyte
Leading Terminating
Anion c1- DL-Ma-
Concentration 0.01 N c4. 0.01M
Counter ion HOC, H, N+H Tris+
PH 7.2, 7.8 c4. 7 (