Frans_M_Everaerts_Isotachophoresis_378342.pdf

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AMINO ACIDS, PEPTIDES AND PROTEINS
Fig.13.9. Isotachopherogram obtained with the operational system listed in Table 13.9. A 0.1-p1
volume of a mixture of ampholytes (LKB) with a ratio of pI3.5-4: PI 4-6: PI 6-8: water of
1:1.5:0.5:20 was injected. A = Increasing UV absorption;R = increasing resistance; 1 = time.
Figs.13.11 and 13.12 show the separations of the sera in Table 13.10 in a narrow-bore
tube using a conductivity and a UV absorption detector (256 nm). The UV traces are
not shown in Figs.13.1 la and 13.12a as they do not give much useful information, but
if they are of interest Fig.13.8a should be consulted. Fig.13.llb and 13.12b must be
compared with Fig.13.10 in order to obtain a comparison of the isotachophoretic and
zone electrophoretic separations of serum proteins. In order to obtain Figs.13.1 lc and
13.12c, the sera were diluted with the ampholytes by first injecting 0.2 p1 of the serum
to be analyzed into the injection block (Fig.7.5) and then 0.2 p1 of the ampholyte mixture.
This procedure was compared with a procedure in which the sera were diluted before the
analysis, in a small bottle. The reproducibilities of both dilution techniques were identical,
but in the first procedure only a small amount of ampholyte mixture is needed.