Tubandt-Hittorf method

Of all the techniques, it is those of Group 1 that are likely to give the most realistic data, simply because they measure transport of charged species only. They are not the easiest experimental techniques to perform on polymeric systems and this probably explains why so few studies have been undertaken. The experimental difficulties associated with the Tubandt-Hittorf method are in maintaining nonadherent thin-film compartments. One way is to use crosslinked films [79], while an alternative has been to use a redesigned Hittorf cell [80]. Although very succesful experimentally, the latter has analytical problems. Likewise, emf measurements can be performed with relative ease [81, 82] it is the necessary determination of activity coefficients that is difficult. 

Measttring the lorric Conductivity by the Short-Circuiting Method Simrrltaneorrs Measrrrement of the Electrorric and Ionic Conductivities Measrtrement of the lorric Corrductivity in Solid Electrolytes The Tubandt or Hittorf Method... 

The pulsed field gradient nuclear magnetic resonance (PFG NMR) technique is experimentally distinct from the radiotracer technique but the principle is very similar. A fraction of the nuclei of each constituent is labelled by flipping their spins and monitoring the diffusion of these species. Both techniques are influenced by the presence of neutral associates unlike the Hittorf/Tubandt method. 

Transport numbers can be measured by several methods. The application of the Hittorf cell (-> Hittorf transport method), that was introduced in 1853, is still the most frequently used technique for the determination of the transport number [iv]. The moving boundary method, analogous to that used by -> Tiselius to measure -> electrophoretic mobilities is also used to measure transport numbers [v]. See also -> Tubandt method. 

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