Thermodynamic behaviour in capillary electrochromatography

Jiskra, Jan; Claessens, H.A.; Cramers, C.A.M.G.

doi:10.1002/1615-9314(20020601)25:9<569::aid-jssc569>3.0.co;2-3

Cited by 14 publications

(10 citation statements)

References 32 publications

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“…Wen found an enthalpy of retention of ‐8.16 kJ/mol for fluorene on a 5 µm C 18 particle column used in a CEC mode . Jiskra found enthalpy values of −6.54 and −8.80 kJ/mol for phenyl hexane on 3 µm C 8 and C 18 particle columns respectively in a CEC mode . Our values are very comparable to these studies.…”

Section: Discussionsupporting

confidence: 86%

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Temperature effects on retention and efficiency of butyl and lauryl acrylate porous polymer monoliths in capillary electrochromatography

Daniels

Waguespack

Hodges

et al. 2019

J of Separation Science

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The development of organic porous polymer monoliths represents an alternative approach to stationary phase design. The use of these materials has helped to rekindle interest in capillary electrochromatography. Although a large number of investigations have explored different monolith recipes, polymerization conditions, and application challenges, few investigations have addressed the fundamentals of this separation mode with this type of material. This study addresses the thermodynamics of the reversed phase retention mechanism on 100% butyl acrylate and 1:3 butyl:lauryl acrylate (volume/volume ratio) porous polymer monoliths used in a capillary electrochromatography mode. Linear van't Hoff plots yield enthalpies of retention of −3.9 to −14.3 kJ/mol on two different, but related columns for five selected hydrophobic analytes across a thirty degree temperature range. Minimum plate heights were only moderately impacted over this temperature range.

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Section: Discussionsupporting

confidence: 86%

“…Jiskra et al. used thermodynamic data in an attempt to understand the retention mechanism in CEC compared to HPLC . They studied four reversed‐phase stationary phases under pressure‐driven and electro‐driven conditions.…”

Section: Introductionmentioning

confidence: 99%

Temperature effects on retention and efficiency of butyl and lauryl acrylate porous polymer monoliths in capillary electrochromatography

Daniels

Waguespack

Hodges

et al. 2019

J of Separation Science

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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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“…5a, they were separated in less than 2 min (v eo = 0.237 cm s −1 ) in presence of an hydroorganic mobile phase containing a 10 mM SDS concentration, in the short end injection mode (l = 8.5 cm). As reported in Table 3, the retention factors calculated in CEC were quite similar to those measured in nano-LC on the same capillary column and with the same mobile phase composition, indicating that the partitioning of these neutral compounds on the reversed-phase is not significantly affected by the elution mode (pressure-or electro-driven mode) as sometimes observed in the literature for other compounds [25][26][27].…”

Section: Separation Of Amphenicol Antibioticsmentioning

confidence: 99%

Separation of basic compounds by capillary electrochromatography on an X-Terra RP18® stationary phase

Valette

Bizet

Demesmay

et al. 2004

Journal of Chromatography A

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Thermodynamic behaviour in capillary electrochromatography

Cited by 14 publications

References 32 publications

Temperature effects on retention and efficiency of butyl and lauryl acrylate porous polymer monoliths in capillary electrochromatography

Temperature effects on retention and efficiency of butyl and lauryl acrylate porous polymer monoliths in capillary electrochromatography

Electrochromatographic retention of peptides on strong cation‐exchange stationary phases

Separation of basic compounds by capillary electrochromatography on an X-Terra RP18® stationary phase

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