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Titolo:
On capillary ion-exchange preconcentration of inorganic anions in open-tubular capillary electrochromatography with elution using transient-isotachophoretic gradients. 2. Characterization of the isotachophoretic gradient
Autore:
Breadmore, MC; Macka, M; Avdalovic, N; Haddad, PR;
Indirizzi:
Univ Tasmania, Hobart, Tas 7001, Australia Univ Tasmania Hobart Tas Australia 7001 ania, Hobart, Tas 7001, Australia Dionex Corp, Sunnyvale, CA 94086 USA Dionex Corp Sunnyvale CA USA 94086Dionex Corp, Sunnyvale, CA 94086 USA
Titolo Testata:
ANALYTICAL CHEMISTRY
fascicolo: 4, volume: 73, anno: 2001,
pagine: 820 - 828
SICI:
0003-2700(20010215)73:4<820:OCIPOI>2.0.ZU;2-2
Fonte:
ISI
Lingua:
ENG
Soggetto:
SOLID-PHASE EXTRACTION; ONLINE PRECONCENTRATION; ZONE ELECTROPHORESIS; SENSITIVITY ENHANCEMENT; CHROMATOGRAPHY; SEPARATION; FLOW;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Life Sciences
Physical, Chemical & Earth Sciences
Citazioni:
24
Recensione:
Indirizzi per estratti:
Indirizzo: Haddad, PR Univ Tasmania, GPO Box 252-75, Hobart, Tas 7001, Australia UnivTasmania GPO Box 252-75 Hobart Tas Australia 7001 ustralia
Citazione:
M.C. Breadmore et al., "On capillary ion-exchange preconcentration of inorganic anions in open-tubular capillary electrochromatography with elution using transient-isotachophoretic gradients. 2. Characterization of the isotachophoretic gradient", ANALYT CHEM, 73(4), 2001, pp. 820-828

Abstract

Diffuse transient-isotachophoretic boundaries can be used as an elution gradient of increasing eluotropic strength to elute inorganic anions that have been preconcentrated on an open-tubular ion-exchange stationary phase prior to electrophoretic separation. The generation and characteristics of these gradients for elution after preconcentration have been investigated. Thegradients are generated by placing a low-mobility, weak ion-exchange competing anion in the capillary (weak electrolyte, WE), and a high-mobility, strong ion-exchange competing anion in the electrolyte vials (strong electrolyte, SE), Application of voltage establishes a diffuse boundary with the composition changing from the weak anion to the strong anion, Comparison of elution gradients generated with different electrolyte systems was accomplished by comparing the eluotropic strength (a function of eluent concentration, ion-exchange selectivity coefficient, and charge) and the shape of the profile as it changes from WE to SE. The ion-exchange selectivity coefficient of the SE competing anion is important in establishing a sharp change in elution strength. A large difference in mobility between the WE and SE competing anions gives an SE with a higher final eluotropic strength, but the slope of the gradient is shallower. This results in a reduction in the efficiency of analyte focusing. To ensure maximum focusing efficiency, the WE and SE electrolytes should be selected such that the SE has the highest possible eluotropic strength for a given concentration of WE. The SE competing anion should also have a sufficiently low electrophoretic mobility to ensurefocusing for the maximum number of analytes, and the mobility difference between the WE and SE competing anions should be as small as possible.

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Documento generato il 10/07/20 alle ore 18:12:13