ISSN:
0935-6304
Keywords:
Metal-ammonia complexes
;
Electroosmosis
;
Field strength
;
Diuretics
;
Resolution
;
Capillary length
;
Chemistry
;
Analytical Chemistry and Spectroscopy
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
The counter ion in CZE separation systems affects resolution, effective field strength and electroosmosis. Alkali metals (lithium, sodium, potassium, and cesium), the ammonium ion, and several complexes of metals with ammonia ([Ag(NH3)2]+, [Cu(NH3)4]2+, [Zn(NH3)4]2+, [Cd(NH3)4]2+, [Ni(NH3)6]2+, and [Co(NH3)6]2+) have been studied for their effect on the separation of diuretics. With the alkali metals the electroosmotic flow velocity decreased and the effective field strength and resolution increased as the hydrated radius of the alkali metal decreased.All the metal-ammonia complexes except that with silver greatly reduced the electroosmotic flow velocity (Veo) and had only a slight effect on the effective field strength (Eeff). Because these complexes had a negligible effect on the ionic strength of the buffer, they enabled high separating power to be maintained during the separation, and hence the use of more energy in the separation system. This yielded better resolution of the compounds, but the analysis time was then compromised.A simultaneous reduction in capillary length and Veo while maintaining the high voltage enabled increased resolution without an increase in analysis time. The ability to control Veo by adding small concentrations (〈 100 μM) of metal complexes to the buffer solution makes it possible to adjust the analysis time and capillary length independently while employing high separation power.
Additional Material:
5 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/jhrc.1240170706
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