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Titolo:
ELECTRICAL DOUBLE-LAYER EFFECTS AND THE ORIGIN OF INDIRECT UV DETECTION IN THE LIQUID-CHROMATOGRAPHY OF A CATIONIC SAMPLE USING A CATIONIC PROBE
Autore:
GLAVINA LLM; CANTWELL FF;
Indirizzi:
UNIV ALBERTA,DEPT CHEM EDMONTON AB T6G 2G2 CANADA UNIV ALBERTA,DEPT CHEM EDMONTON AB T6G 2G2 CANADA
Titolo Testata:
Analytical chemistry
fascicolo: 13, volume: 68, anno: 1996,
pagine: 2228 - 2235
SICI:
0003-2700(1996)68:13<2228:EDEATO>2.0.ZU;2-Q
Fonte:
ISI
Lingua:
ENG
Soggetto:
ION-PAIR CHROMATOGRAPHY; OCTADECYLSILYL BONDED PHASES; RETENTION MODELS; POLYSTYRENE POLYMERS; SYSTEM PEAKS; MOBILE PHASE; ORGANIC IONS; MECHANISM; STRENGTH; SORPTION;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Science Citation Index Expanded
Citazioni:
34
Recensione:
Indirizzi per estratti:
Citazione:
L.L.M. Glavina e F.F. Cantwell, "ELECTRICAL DOUBLE-LAYER EFFECTS AND THE ORIGIN OF INDIRECT UV DETECTION IN THE LIQUID-CHROMATOGRAPHY OF A CATIONIC SAMPLE USING A CATIONIC PROBE", Analytical chemistry, 68(13), 1996, pp. 2228-2235

Abstract

Two cations, tetra-n-butylammonium (TBA(+)) and (4-nitrobenzyl)trimethylammonium (NBTA(+)), are simultaneously sorbed on the bonded phase sorbent Partisil-10 ODS-3 from water at various ionic strengths. The non-UV-absorber TBA(+) is thought of as the sample ion and the UV-absorber NBTA(+) as the probe ion in an indirect detection system. in the sorbed state, the two ions reside at different charge planes: NBTA(+) isvery close to the ODS-water interface, and TBA(+) is about 11 Angstrom deeper into the ODS phase. Both ions contribute to the electrical potential psi(I) at the NBTA(+) charge plane, which can be calculated from an electrical triple-layer model. The sorption of TBA(+) influencesthe amount of NBTA(+) sorbed both by raising psi(I) and by altering the amount of space available for NBTA(+). The former effect is greaterthan the latter at ionic strengths up to at least 0.5 mol/L. For the latter effect, the direction and magnitude of the influence of TBA(+) on available space both change with ionic strength (c). At low c, sorbed TBA(+) increases the amount of space available for NBTA(+) by disrupting the conformation of the alkyl chains of the ODS phase, At high c, sorbed TBA(+) decreases the amount of space available by competing with NBTA(+) for space. This dramatically different effect of TBAf on available space at low and high c occurs because higher c produces botha weaker interaction of the ODS alkyl chains with water and a reorientation of NBTA(+) from flat to perpendicular in the ODS phase.

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Documento generato il 08/07/20 alle ore 07:43:15