Sm. Lunte et Tj. Oshea, PHARMACEUTICAL AND BIOMEDICAL APPLICATIONS OF CAPILLARY ELECTROPHORESIS ELECTROCHEMISTRY/, Electrophoresis, 15(1), 1994, pp. 79-86
The use of capillary electrophoresis/electrochemistry (CEEC) for the a
nalysis of microdialysis samples obtained for pharmacokinetic and neur
ochemical studies is described, as well as the development of new type
s of electrodes and waveforms which increase the selectivity of this t
echnique for specific classes of analytes. CEEC with a carbon fiber el
ectrode was employed for the analysis of microdialysis samples. Microd
ialysis is an in vivo sampling technique that yields very small sample
s for analysis (less than 1 mu L). Therefore, capillary electrophoresi
s, with its small volume requirements, is an excellent choice for the
analytical method. CEEC was used to study the pharmacokinetics of L-do
pa and the release of aspartate and glutamate following a high K+ infu
sion in the brain. Several modified electrodes which increase the appl
icability of CEEC in pharmaceutical and biomedical analysis are descri
bed. One of these is a gold/mercury electrode which is highly selectiv
e for thiols and was used for the determination of glutathione in a ra
t brain. An alternative method for the detection of thiols employed a
chemically modified electrode containing cobalt phthalocyanine. In thi
s case, an electrocatalyst reduces the overpotential of thiols at the
carbon electrode and makes it possible to detect them at a much lower
and more selective oxidation potential. This electrode was used for th
e detection of cysteine in urine. The development of pulsed amperometr
ic detection for capillary electrophoresis is also described and is de
monstrated by the detection of glucose in blood. Lastly, a method for
the detection of peptides based on the formation of a copper complex a
nd detection at a carbon fiber electrode is discussed.