High performance capillary electrophoresis - T.E.A.M.

Modes
micelle migration varies and depends on the micelle charge
and the rate of EOF. Generally, high pH buffers are used to
maintain reasonable EOF and ensure migration direction.
3.2.1 Applications of MEKC
MEKC is a dynamic mode of CE since it can be used for
charged and uncharged analytes and for a wide range of
substances with hydrophilic or hydrophobic characteristics.
Applications include amino acids, nucleotides, vitamins, a
wide range of pharmaceuticals, aromatic hydrocarbons, and
explosive constituents, to name a few.
For pharmaceuticals, MEKC has been used for the determination
of active drugs in tablets, creams, and injectable
formulations. The separation of the active ingredients of a
cold-relief preparation using SDS micelles is illustrated in
figure 37. The migration order is determined by solute
lipophilicity and polarity. Only cationic, and to a certain
extent, neutral species become incorporated with the
micelle. In this work, the effect of SDS concentration and
type, pH, and organic modifier were studied. In addition,
quantitative analysis of Novapon granules was performed
1 Acetaminophen
2 Caffeine
3 Sulpyrin
4 Naproxen
5 Guaifenesin
6 Impurity
7 Phenacetin
8 Ethenzamide
9 4-isopropylantipyrine
10 Noscapine
11 Chlorpheniramine
1 2 3
4
5
6
7 8 9
10 11
Figure 37
MEKC separation of cold-relief medicine
constituents 17
Conditions: 20 mM phosphate-borate,
100 mM SDS, pH 9, V= 20 kV,
L = 65 cm, id = 50 mm, l = 210 nm
5 10 15 20
Time [min]
67