CE in a Nonuniform Capillary Modulated by a Cylindrical Insert, and Zone-Narrowing Effects during Sample Injection

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• 作者：Alexander V. Stoyanov ; Zhen Liu ; and Janusz Pawliszyn
• 刊名：Analytical Chemistry
• 出版年：2003
• 出版时间：July 15, 2003
• 年：2003
• 卷：75
• 期：14
• 页码：3656 - 3659
• 全文大小：59K
• 年卷期：v.75,no.14(July 15, 2003)
• ISSN：1520-6882

文摘

The electrophoretic behavior of an analyte in a capillaryconsisting of two parts of different cross section has beeninvestigated. Modulation of the cross-sectional area of theseparation channel has been achieved by inserting acylindrical fiber different distances into the capillary. Itwas shown that the zone injected into the capillary partwith smaller cross section could be moved using electromigration into the wider part of the capillary with zonecompression. As we observed, the zone narrowed longitudinally in the wide part of the capillary in accordancewith the ratio of the electric field strength in the two partsof the capillary. The concentration of plug introduced intothe capillary by electroinjection can be increased by useof low-conductivity sample buffer. Efficient introductionof extracted analytes desorbed from an SPME fiber to theseparation channel was achieved using this approach.Thermoinduced effects caused by temperature increasein the narrow part of the capillary and their influence onsample stacking are analyzed. Possible applications of theeffect observed to the sample introduction optimizationare also discussed in this study.