Capillary electrochromatography: An alternative to HPLC and CE

Mistry, Kavita; Krull, Ira S.; Grinberg, Nelu

doi:10.1002/1615-9314(20021101)25:15/17<935::aid-jssc935>3.0.co;2-d

Cited by 78 publications

(31 citation statements)

References 323 publications

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“…CEC, which is often described as a hybrid of CZE and LC [6,7], has demonstrated higher separation efficiencies and flow permeabilities than capillary HPLC [8][9][10][11][12][13][14][15][16][17][18][19][20][21][22]. The use of silica-based stationary phases with reversed-phase properties in CEC is well established at medium and higher mobile phase pH, where dissociated residual silanol groups provide the necessary surface charge for a suitable EOF.…”

Section: Introductionmentioning

confidence: 99%

Electrochromatographic retention of peptides on strong cation‐exchange stationary phases

Nischang¹,

Höltzel²,

Tallarek³

2010

Electrophoresis

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We analyze the systematic and substantial electrical field-dependence of electrochromatographic retention for four counterionic peptides ([Met5]enkephalin, oxytocin, [Arg8]vasopressin, and luteinizing hormone releasing hormone (LHRH) ) on a strong cation-exchange (SCX) stationary phase. Our experiments show that retention behavior in the studied system depends on the charge-selectivity of the stationary phase particles, the applied voltage, and the peptides' net charge. Retention factors of twice positively charged peptides ([Arg8]vasopressin and LHRH at pH 2.7) decrease with increasing applied voltage, whereas lower charged peptides (oxytocin and [Met5]enkephalin at pH 2.7, [Arg8]vasopressin and LHRH at pH 7.0) show a concomitant increase in their retention factors. The observed behavior is explained on the basis of electrical fieldinduced concentration polarization (CP) that develops around the SCX particles of the packing. The intraparticle concentration of charged species (buffer ions, peptides) increases with increasing applied voltage due to diffusive backflux from the enriched CP zone associated with each SCX particle. For twice charged and on the SCX phase strongly retained peptides the local increase in mobile phase ionic strength reduces the electrostatic interactions with the stationary phase, which explains the decrease of retention factors with increasing applied voltage and CP intensity. Lower charged and weaker retained peptides experience a much stronger relative intraparticle enrichment than the twice-charged peptides, which results in a net increase of retention factors with increasing applied voltage. The CP-related contribution to electrochromatographic retention of peptides on the SCX stationary phase is modulated by the applied voltage, the mobile phase ionic strength, and the peptides' net charge and could be used for selectivity tuning in difficult separations.

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Section: Introductionmentioning

confidence: 99%

Electrochromatographic retention of peptides on strong cation‐exchange stationary phases

Nischang¹,

Höltzel²,

Tallarek³

2010

Electrophoresis

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“…On the other hand, in CEC systems, electrokinetic effect can result in the electro-osmosis of fluid phase on a charged surface, as well as electrophoresis of charged solutes, enhancing the mass transfer rate inside charged porous particles [5 -8]. It is the electric double layer that made the electro-osmosis feasible for increasing the mass transport in both the analytical CEC [9] and the preparative electrochromatography [10 -13]. Earlier designs of preparative electrochromatography, mostly with a view to the size-exclusion chromatography, fixed the electrodes on the two ends of the column; that is, the electric field was applied in the axial direction [12 -18].…”

Section: Introductionmentioning

confidence: 99%

High‐capacity purification of hen egg‐white proteins by ion‐exchange electrochromatography with an oscillatory transverse electric field

Yuan

Zhao

Dong

et al. 2006

J of Separation Science

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Original PaperHigh-capacity purification of hen egg-white proteins by ion-exchange electrochromatography with an oscillatory transverse electric fieldThe ion-exchange electrochromatography with an oscillatory electric field perpendicular to the mobile-phase flow driven by pressure (pIEEC) was used to separate hen egg-white (HEW) proteins. The results were compared with those of normal ionexchange chromatography (IEC). The column was designed as three-compartment rectangular column of 2-mL with dimensions (length6width6depth) of 4061065 mm 3 and the electric field was applied across the direction of column width. Q Sepharose FF was packed into the central compartment as the chromatographic bed. It was confirmed that the dynamic binding capacity (DBC) of different proteins (ovotransferrin and ovalbumin) in the HEW solution increased 2.3 times when an oscillatory electric current of 30 mA at 1/20 Hz was applied in the transverse column direction. Then, the HEW proteins were separated by the pIEEC at loading amounts 2.3-fold higher than those by the IEC. When the feedstock of about one-third of the DBC was applied to the columns (i. e., 7 mL for the pIEEC and 3 mL for the IEC), similar separation efficiencies of the two chromatographic modes were achieved. Both the recovery yield and purity reached 73% to over 90%. The results indicate that the pIEEC is promising for high-capacity purification of proteins.

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“…The latter appears to pose a crucial limitation to CEC at the moment. Basic considerations and the theory of CEC have been reviewed [125,126]. An Index Pharma STN data base search 2002 revealed 52 hits for the key words "chiral capillary electrochromatography" and only 8 hits were found when restricting the search to "pharmaceutical".…”

Section: Capillary Electrochromatographymentioning

confidence: 99%

Pharmaceutical and biomedical applications of chiral capillary electrophoresis and capillary electrochromatography: An update

Scriba¹

2003

Electrophoresis

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Pharmaceutical and biomedical applications of chiral capillary electrophoresis and capillary electrochromatography: An updateCapillary electrophoresis is often considered an ideal method for the chiral analysis of compounds due to the high separation power of the technique and has therefore found widespread acceptance for the analysis of drugs and pharmaceuticals. In contrast, capillary electrochromatography is still more or less in an infancy state searching for its place among the analytical separation techniques although interesting applications have been published. The present review summarizes recent developments and applications of chiral pharmaceutical analysis by electromigration techniques published in 2002 and early 2003.

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Capillary electrochromatography: An alternative to HPLC and CE

Cited by 78 publications

References 323 publications

Electrochromatographic retention of peptides on strong cation‐exchange stationary phases

Electrochromatographic retention of peptides on strong cation‐exchange stationary phases

High‐capacity purification of hen egg‐white proteins by ion‐exchange electrochromatography with an oscillatory transverse electric field

Pharmaceutical and biomedical applications of chiral capillary electrophoresis and capillary electrochromatography: An update

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