Frans_M_Everaerts_Isotachophoresis_378342.pdf

THERMOMETRIC RECORDING
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It-- I
a b
Fig.6.5. Isotachopherogram showing the separation of some anionic species in the operational system
at pH 6. The signals were derived from thermometric recording of the passage of zone boundaries.
T= Increasing temperature; t = time. The injected volumes were (a) 1 pl, (b) 2 p1 and (c) 3 pl.
1 = Chloride (leading ion); 2 = oxalate; 3 = formate; 4 = acetate; 5 = p-chloropropionate; 6 = glutamate
(terminating ion).
The steady state during isotachophoretic separation is attained earlier if a smaller amount
of ionic material is injected. Thus, although this isotachopherogram simulates an incom-
plete separation, the steady state has been reached*. From this isotachopherogram,
however, only quantitative information can be deduced, so the actual sequence must be
known. It should be remembered that for quantitative analyses, only the transition of
*This is in contradiction to similar looking records in chromatography.
C