Anion-exchange capillary electrochromatography with indirect UV and direct contactless conductivity detection
Conductivity detection is applied to ion‐exchange capillary electrochromatography (IE‐CEC) with a packed stationary phase, using a capacitively coupled contactless conductivity detector with detection occurring through the packed bed. Columns were packed with a polymeric latex‐agglomerate anion‐exch...
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Published in | Electrophoresis Vol. 22; no. 7; pp. 1273 - 1281 |
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Main Authors | , , , |
Format | Journal Article |
Language | English |
Published |
Hoboken
Wiley Subscription Services, Inc., A Wiley Company
01.05.2001
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Subjects | |
Online Access | Get full text |
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Summary: | Conductivity detection is applied to ion‐exchange capillary electrochromatography (IE‐CEC) with a packed stationary phase, using a capacitively coupled contactless conductivity detector with detection occurring through the packed bed. Columns were packed with a polymeric latex‐agglomerate anion‐exchanger (Dionex AS9‐SC). A systematic approach was used to determine suitable eluants for IE‐CEC separations using simultaneous indirect UV and direct conductivity detection. Salicylate and p‐toluenesulfonate were identified as potential eluant competing anions having sufficient eluotropic strength to induce changes in separation selectivity, but salicylate was found to be unsuitable with regard to baseline stability. It was also found for both indirect UV and direct conductivity detection that homogenous column packing was imperative, and monitoring of the baseline could be used to assess the homogeneity of the packed bed. Using a p‐toluenesulfonate eluant, the separation of eight common anions was achieved in 2.5 min. Direct conductivity detection was found to be superior to indirect UV detection with regard to both baseline stability and detection sensitivity with detection limits of 4–25 μg/L being obtained. However, the calibration for each anion was not linear over more than one order of magnitude. When using conductivity detection, the concentration of the eluant could be varied over a wider range (2.5–50 mM p‐toluenesulfonate) than was the case with indirect UV detection (2.5–10 mM), thereby allowing greater changes in separation selectivity to be achieved. By varying the concentration of p‐toluenesulfonate in the eluant, the separation selectivity could be manipulated from being predominantly ion‐exchange in nature (2.5 mM) to predominantly electrophoretic in nature (50 mM). |
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Bibliography: | ArticleID:ELPS1273 ark:/67375/WNG-9BQ2VRTX-V istex:4D895916B072572B34BD790A8163FCC1F83286EC ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 23 |
ISSN: | 0173-0835 1522-2683 |
DOI: | 10.1002/1522-2683(200105)22:7<1273::AID-ELPS1273>3.0.CO;2-U |