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Titolo:
SYSTEM PEAKS IN CAPILLARY-ZONE-ELECTROPHORESIS .3. PRACTICAL RULES FOR PREDICTING THE EXISTENCE OF SYSTEM PEAKS IN CAPILLARY-ZONE-ELECTROPHORESIS OF ANIONS USING INDIRECT SPECTROPHOTOMETRIC DETECTION
Autore:
MACKA M; HADDAD PR; GEBAUER P; BOCEK P;
Indirizzi:
ACAD SCI CZECH REPUBL,INST ANALYT CHEM,VEVERI 97 CZ-61142 BRNO CZECH REPUBLIC ACAD SCI CZECH REPUBL,INST ANALYT CHEM CZ-61142 BRNO CZECH REPUBLIC UNIV TASMANIA,DEPT CHEM,SEPARAT SCI GRP HOBART TAS 7001 AUSTRALIA
Titolo Testata:
Electrophoresis
fascicolo: 11, volume: 18, anno: 1997,
pagine: 1998 - 2007
SICI:
0173-0835(1997)18:11<1998:SPIC.P>2.0.ZU;2-4
Fonte:
ISI
Lingua:
ENG
Soggetto:
ISOTACHOPHORESIS; MOBILITIES;
Keywords:
SYSTEM PEAKS; INDIRECT DETECTION; CAPILLARY ZONE ELECTROPHORESIS;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Science Citation Index Expanded
Citazioni:
22
Recensione:
Indirizzi per estratti:
Citazione:
M. Macka et al., "SYSTEM PEAKS IN CAPILLARY-ZONE-ELECTROPHORESIS .3. PRACTICAL RULES FOR PREDICTING THE EXISTENCE OF SYSTEM PEAKS IN CAPILLARY-ZONE-ELECTROPHORESIS OF ANIONS USING INDIRECT SPECTROPHOTOMETRIC DETECTION", Electrophoresis, 18(11), 1997, pp. 1998-2007

Abstract

A theoretical and experimental study of the existence and evolution of system peaks in capillary zone electrophoresis (CZE) with indirect spectrophotometric detection is presented with respect to the effect ofthe number of colons present in the background electrolyte (BGE). It is shown that in BGEs having only one colon (i.e., the UV-absorbing probe anion), the sample produces only negative peaks due to each analyte anion and no system peaks, with the number of sample peaks corresponding to the number of analytes present in the sample injected. In BGEscontaining two colons, a sample with one analyte anion produces one negative indirect detection peak and one system peak. The transition between BGEs having one colon and those with two colons has also been studied and it has been shown that an addition of ca. 5% of the second colon to a single colon BGE causes the resulting BGE to behave macroscopically as a regular two-colon BGE. A descriptive model is proposed, based on transient isotachophoresis (transient stacking) of the sample species and of the colon from the BGE which has the closest mobility to the sample ion. This model explains qualitatively the formation and evolution of the sample peak (containing the sample species and being detected by indirect detection due to displacement of the UV-absorbingprobe in its zone) and the system peak (containing no sample species and being a vacancy in the continuum of colons of the BGE). It is shown that the system peak may be positive or negative as it corresponds to the situation where the vacancy of one component of the BGE results in an enhanced concentration of the other component. It has been demonstrated that the system peak is created by a vacancy of that componentof the BGE which has the greatest difference in mobility relative to that of the sample species. On indirect detection in BGEs containing two colons the sample displaces predominantly the BGE colon which has amobility closest to that of the analyte anion. In systems with BGEs containing two colons, a sample having n analytes produces n sample peaks and one system peak, the sign and magnitude of which are dependent on the sum of the UV absorbances of the analytes involved. The effect of bicarbonate from atmospheric CO2 has also been studied and it has been shown that weakly alkaline BGEs with a single anionic UV-absorbingcolon, such as those currently used for anionic analyses with indirect detection, may suffer from the presence of system peaks due to bicarbonate.

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Documento generato il 02/07/20 alle ore 22:08:28