Advances in capillary electrochromatography and micro‐high performance liquid chromatography monolithic columns for separation science

Legido‐Quigley, Cristina; Marlin, Nicola D.; Melin, Virginie; Manz, Andreas; Smith, Norman W.

doi:10.1002/elps.200390136

Cited by 213 publications

(120 citation statements)

References 100 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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“…[30][31][32][33][34] The characteristics of the columns were also solution for the high speed separation operated with relatively affected by the polymerization conditions, such as the low back pressure. [8][9][10][11] The high speed separation using temperature and the radical generation rate. [35][36][37] In other words, monolithic column have been widely studied.…”

Section: Introductionmentioning

confidence: 99%

Methacrylate-ester-based Reversed Phase Monolithic Columns for High Speed Separation Prepared by Low Temperature UV Photo-polymerization

2009

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Butyl methacrylate-based reversed phase capillary monolithic columns were prepared using ultraviolet (UV) photo-polymerization. The effects of two photo-polymerization conditions (UV irradiation intensity and polymerization temperature) on the column characteristics were investigated. Both the higher UV irradiation intensity and the lower polymerization temperature lead to the superior column efficiency. The column prepared under the optimized conditions was evaluated through the separation of the uracil and five alkylbenzenes in the linear flow rate range of 1 -110 mm/s. At 1 mm/s, all analytes were well separated (N = 36000 -45000 plates/m). The high speed separation within 8 s was performed at 110 mm/s (back pressure, 33 MPa) at room temperature, whereas the peaks eluted earlier were overlapped partially. The relationship between the flow rate and the back pressure indicated that some kind of structural change of the monolith might occur in 50 -110 mm/s, although no visible or hysteresis changes of the monolith were observed after the measurement.

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“…[1][2][3][4][5] Materials suitable for the fabrication of the monolithic bed are divided into two main categories: silica [6][7][8] and polymer [9][10][11][12][13][14][15][16] monolith. Silica monolithic columns have well-controlled pore structure, good mechanical strength, and high column efficiency, 7,8 while polymer monolithic columns have unique features such as applicability over a wide pH range and simplicity of preparation.…”

Section: Introductionmentioning

confidence: 99%

Low-flow-resistance Methacrylate-based Polymer Monolithic Column Prepared by Low-conversion Ultraviolet Photopolymerization at Low Temperature

et al. 2013

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Advances in capillary electrochromatography and micro‐high performance liquid chromatography monolithic columns for separation science

Cited by 213 publications

References 100 publications

Electrochromatographic retention of peptides on strong cation‐exchange stationary phases

Electrochromatographic retention of peptides on strong cation‐exchange stationary phases

Methacrylate-ester-based Reversed Phase Monolithic Columns for High Speed Separation Prepared by Low Temperature UV Photo-polymerization

Low-flow-resistance Methacrylate-based Polymer Monolithic Column Prepared by Low-conversion Ultraviolet Photopolymerization at Low Temperature

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