Frans_M_Everaerts_Isotachophoresis_378342.pdf

ADDITIVES TO THE ELECTROLYTES 189
narrow-bore tubes made of PTFE in combination with a conductivity detector made of
Perspex, sharp isotachopherograms were obtained only when a surfactant was added
(Fig.6.44). When the UV detector was used it was also found that an additive is necessary,
as can be seen in Fig.6.44.
When the conductivity detector was made of TPX, the additives showed much less
influence on the detection with the conductivity detector. Now, the wetting capacity of
Fig.6.44. Resolution in the absence (below) and presence (above) of surfactants. When no surfactants
were added to the electrolytes, the conductimetric detection had poor resolution. This fgure also
shows that additives need to be added when a UV detector is used. This proves that the electroendosmotic
profite is reduced by the addition of a surfactant, which increases the viscosity in the vicinity of the
wall. Sample: test mixture (Fig.6.15).