Frans_M_Everaerts_Isotachophoresis_378342.pdf

REFERENCES 201
seen. Again it is clear that in order to observe a sample zone with a thermometric detector
the zone length must be greater (Table 6.2) than if a high-resolution detector is applied
(UV, conductimeter). Hence more sample has been introduced into the system and
consequently a longer time of analysis is needed.
In Fig.6.51, an analysis under conditions identical with those in Fig.6.50 is shown,
recording being effected with a linearized conductimeter (Fig.6.18) and a W-absorption
detector (256 nm) (Fig.6.26).
It should be pointed out that the various isotachopherograms shown in this chapter
are given mainly for pattern recognition, in order to show different effects such as
sharpness of the profiles, electrode reactions and impurities. It is difficult to compare
one isotachopherogram with another, although a single test mixture of anions was used.
In preparing the manuscript, the various isotachopherograms were treated photographically
in order to make comparisons simpler. In the Section Applications (Chapters 8-17)
the time axis is also given on the relevant isotachopherograms, so that the qualitative and
quantitative information can be deduced more easily.
Although electrode reactions may sometimes still occur during detection with a
conductimeter with the electrodes in direct contact with the electrolyte, its resolution is
lugh compared with that of other types of universal detectors. Moreover, possible coating
of the electrode can easily be observed by using a combination of an a.c. and d.c. detector
(see also Fig.8.1.). We recommend that the entire system should be cleaned from time to
time with a non-ionic surfactant, which can be purified by running it through a mixed-
bed ion exchanger, because all types of material may be adsorbed on walls made of
Perspex, TPX, Pt or even PTFE. When adsorbed, these impurities change the {-potential
and hence the electroendosmosis, and thus the resolution of both conductivity and UV
absorption detectors is decreased. For effective rinsing of the electrophoretic equipment,
we recommend the surfactant Extran (Merck, Darmstadt, G.F.R).
REFERENCES
1 F.M. Everaerts, Thesis, University of Technology, Eindhoven, 1968.
2 F.M. Everaerts and Th.P.E.M. Verheggen,J. Chromatogr., 53 (1970) 315.
3 F.M. Everaerts and Th.P.E.M. Verheggen, in P.G. Righetti (Editor), Progress in Isoelectric Focusing
and Zsotachophoresis, North-Holland, Amsterdam, and Elsevier, New York, 1975, p. 309.
4 F.M. Everaerts, J.L. Beckers and Th.P.E.M. Verheggen, Ann. NY. Acad. Sci., 209 (1973) 419.
5 F.M. Everaerts, Graduation Rep., University of Technology, Eindhoven, 1964.
6 F.M. Everaerts and Th.P.E.M. Verheggen, J. Chromatog., 91 (1974) 837.
7 F.M. Everaerts and P.J. Rommers,J. Chromatogr., 91 (1974) 809.
8 F.M. Everaerts and Th.P.E.M. Verheggen,J. Chromatogr., 73 (1972) 193.
9 F.M. Everaerts, internal report, University of Technology, Eindhoven, 972.
10 A. Vestermark and B. Sjodin, J. Chromatogr., 71 (1972) 588.
11 L. Arlinger and H. Lundin, Protides Biol. Fluids, Proc. Colloq., 21 (1973) 667.
12 A.J.P. Martin and F.M. Everaerts, Anal. Chim. Ac~Q, 38 (1967) 233.
13 A.J.P. Martin and F.M. Everaerts, Proc. Roy. SOC., Ser. A, 316 (1970) 493.
14 B.P. Konstantinov and O.V. Oshurkova, Sov. Phys.-Tech. Phys., 37 (1967) 1745.
15 I. Vacik, J. Zuska, F.M. Everaerts and Th.P.E.M. Verheggen, Chem. Listy, 66 (1972) 545.
16 F.M. Everaerts, J. Vacik, Th.P.E.M. Verheggen and J. Zuska, J. Chromatogr., 49 (1970) 262.
17 M. Coxon and M.J. Binder,J. Chromatogr., 101 (1974) 1.