Estimation of the Molecular Weight of Ions by Isotachophoresis

A correlative equation relating the molecular weight of ions to the relative step height in an isotachopherogram was derived : hR=a+b M/|Z|, in which hR, M, |Z|, a and b are the relative step height with chloride ion as a standard, the molecular weight, the electric charge of ions and two constants, respectively. Therefore, the molecular weight of ions may be estimated from the relative step height in an isotachopherogram, when the electric charge is known. The equation for carboxylic acids was : hR=0.65+0.01 M/|Z|. The optimum pH of electrolytes for the estimation of molecular weight or for the separation of ions may be determined from the relative step height-pH curves obtained on the basis of this equation.