Frans_M_Everaerts_Isotachophoresis_378342.pdf

SEPARATION OF CATIONIC SPECIES IN METHANOL 367
TABLE 16.4
OPERATIONAL SYSTEM (UNBUFFERED) SUITABLE FOR CATIONIC SEPARATIONS (MHCI)
Solvent: CH,OH.
Electric current (MA): Ca. 50.
Purification: Methanol (95%, technical grade) was purified by running it through a column
filled with a mixed-bed ion exchanger (Merck V).
Electrolyte
Leading Terniinating
+
Cation
Concentration
Counter ion
H+
0.01 N
c1-
CdZ
C'. 0.01 N
c1-
PH - -
Additive None None
TABLE 16.5
OPERATIONAL SYSTEM AT pH 7.4 SUITABLE FOR CATIONIC SEPARATIONS (MKAC)
Solvent: CH,OH.
Electric current (MA): Ca. 50.
Purification: Methanol (9576, technical grade) was purified by running it through a column
filled with a mixed-bed ion exchanger (Merck V).
Electrolyte
Leading Terminating
Cation K+ Cd"
Concentration 0.01 N Ca. 0.01 N
Counter ion CH, COO- c1-
PH 7.4 -
Additive None None
leading ion being W and the terminating ion Cuz+. In Fig.16.6, the isotachopherogram is
given for the separation of a mixture of (CH3)41V, (C2H5)4N+, NH;, K', Na', Ca2+, Li+,
Co2+, Mn2+ and Cu2+, the leading ion being H’ and the terminating ion Cd2+.
16.3.2. The operational system MKAC
In this system, the leading electrolyte is potassium acetate in methanol adjusted to a
pH of 7.4 by adding acetic acid. The pH is measured with a glass electrode and a calomel
electrodel filled with an aqueous saturated solution of potassium chloride, as a reference
electrode; The terminator used is cadmium chloride in methanol. There are large differ-
ences in clornparison with the step heights of the cations in the system MHC1, particularly