Frans_M_Everaerts_Isotachophoresis_378342.pdf

GENERAL EQUATIONS
4.2.4. Modified Ohm’s law
Working at a constant current density:
i/C = constant = E h,
(The Faraday constant is included in G). The overall electrical conductivity of a zone is
the sum of the values cinz,lzj\, and consequently
i
u nAY
I/G=EU coH,u’ptoH,u+cH,umH,u + C 2 (~zA;ilcA,.,u, zALi mAr,u, zA -i) +
r=O i=O
J
Substitution of eqns. 4.7 and 4.9 into eqn. 4.22 gives for the modified Ohm’s law:
4.2.5. Parameters and equations
51
(4.21)
(4.22)
1
(4.23)
The general equations given above describe the moving-boundary model. If the
compositions of the leading electrolyte and of the sample are known, all parameters
can be calculated. In Table 4.1, all parameters, known parameters and equations are
listed for all zones. For each ionic species, both n + 1 ionic concentrations and n
equilibrium equations are present. Using eqns. 4.7 and 4.9, all ionic concentrations can
be expressed as the total concentration for each type of ion. In this way, both the number