Frans_M_Everaerts_Isotachophoresis_378342.pdf

200 DETECTION SYSTEMS
f.
11 L 1’
1’
Fig.6.51. Isotachophoretic separation of the test mixture of anions (Fig.6.15) in the operational
system histidinelhistidine hydrochloride at pH 6 (Table 12.1). Conductimetric detection was carried
out with a linear conductimeter. The UV trace was derived from a UV absorption detector (not
chopped) at 256 nm. The speed of the recorder chart paper was 6 cm/min and the time of analysis
was 12 min. The electric current was stabilized at 70 PA. R = increasing electric resistance; A =
increasing UV absorption; t = time. 1 = Chloride; 2 = sulphate; 3 = chlorate 4 = chromate; 5 =
malonate; 6 = pyrazole-3,5-dicarboxylate; 7 = adipate; 8 = acetate; 9: p-chloropropionate; 10 =
glutamate; X = impurity, possibly propionate (a degradation product of p-chloropropionic acid).
operational system at pH 6 (Table 12.1), are shown. The traces of the linear signals
have been equalized photographically in order that a valid comparison of the results can
be made. The recording of the final sharpness of the zone boundaries and the difference
in the time of analysis with a high-resolution and a low-resolution detector can clearly be