Ionic conductance of nanopores in microscale analysis systems: Where microfluidics meets nanofluidics

Höltzel, Alexandra; Tallarek, Ulrich

doi:10.1002/jssc.200600427

Cited by 143 publications

(158 citation statements)

References 175 publications

Supporting

Mentioning

154

Contrasting

Unclassified

Order By: Relevance

“…1B) show clear deviations from linearity only for ionic strengths430 mM, so that Joule-heating accounts for the nonlinear EOF behavior at higher ionic strengths (a plot of u eo versus electrical current is linear, data not shown). The nonlinear EOF behavior observed at lower ionic strengths (with a nonlinear u eo -current relation) is caused by CP-based nonequilibrium electroosmosis, as extensively studied by our group [22,[44][45][46]. Increasing the buffer pH from pH 2.7 to 7.0 results in slightly higher EOF velocities due to dissociation of residual silanol groups of the stationary phase, but as the electrical current remains almost unchanged (Fig.…”

Section: Eof Dynamicsmentioning

confidence: 75%

“…Compared with the unpacked capillaries used in CZE, coupled mass and charge transport in packed capillaries are much more complex due to concentration polarization (CP), which is induced locally around any stationary phase particle of the bed by the applied electrical field [43][44][45][46][47]. CP originates in electrical double layer (EDL) overlap inside the charged pores of porous particles that are characterized by mesopore (and even micropore) sizes.…”

Section: Introductionmentioning

confidence: 99%

“…It involves the formation of background ion concentration gradients at charge-selective interfaces upon the passage of an electrical current normal to these interfaces [50]. CP for a cation-selective stationary phase particle is characterized by a depleted CP zone along its anodic hemisphere, where counterions enter the particle in the direction of the applied field, and an enriched CP zone along its cathodic hemisphere, where counterions leave the particle [43][44][45][46][47].…”

Section: Introductionmentioning

confidence: 99%

“…A particular property of the CP zones is their local gradients in ionic strength, thus, in local electrical conductivity [45]. These gradients imply the inherent existence of electrical field gradients in CEC around as well as across all porous particles of a packing and are expected to impact the migration and zone dispersion of charged analytes.…”

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Electrochromatographic retention of peptides on strong cation‐exchange stationary phases

Nischang¹,

Höltzel²,

Tallarek³

2010

Electrophoresis

Self Cite

View full text Add to dashboard Cite

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.

show abstract

Section: Eof Dynamicsmentioning

confidence: 75%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Electrochromatographic retention of peptides on strong cation‐exchange stationary phases

Nischang¹,

Höltzel²,

Tallarek³

2010

Electrophoresis

Self Cite

View full text Add to dashboard Cite

show abstract

“…100,101 Here, the persistence of the hydration and the dragged water wedge size are controlling factors in ion transport.…”

Section: Discussionmentioning

confidence: 99%

Ion Transport through a Water–Organic Solvent Liquid–Liquid Interface: A Simulation Study

2014

View full text Add to dashboard Cite

Ion interactions and partitioning at the water-organic solvent interface and the solvation characteristics have been characterized by molecular dynamics simulations.More precisely, we study sodium cation transport through water-cyclohexane, water-1, 2-dichloroethane, and water-pentanol interfaces providing a systematic characterization of the ion interfacial behavior including barriers against entering the apolar phase, as well as, characterization of the interfaces in the presence of the ions. We find a sodium depletion zone at the apolar interface and persistent hydration of the cation when entering the apolar phase. The barrier against the cation entering the apolar phase and ion hydration depend strongly on specific characteristics of the organic solvent. The strength of both barrier and hydration shell binding (persistence of the cation hydration) go with the apolarity and the surface tension at the interface, that is, both decrease in order cyclohexane-water > 1, 2-dichloroethane-water > pentanol-water. However, the size of the hydration shell measured in water molecules bound by the cation entering the less polar phase behaves oppositely with the cation carrying most water to the pentanol phase, and a much smaller in size, but very tightly bound water shell to cyclohexane. We discuss the implications of the observations for ion transport through the interface of immiscible, or poorly miscible liquids, and for materials of confined ion transport such as ion conduction membranes or biological ion channel activity.

show abstract

Nanofluidic Devices and Their Potential Applications

Abgrall¹,

Bancaud²,

Joseph³

2010

Microfluidic Devices in Nanotechnology

View full text Add to dashboard Cite

Ionic conductance of nanopores in microscale analysis systems: Where microfluidics meets nanofluidics

Cited by 143 publications

References 175 publications

Electrochromatographic retention of peptides on strong cation‐exchange stationary phases

Electrochromatographic retention of peptides on strong cation‐exchange stationary phases

Ion Transport through a Water–Organic Solvent Liquid–Liquid Interface: A Simulation Study

Nanofluidic Devices and Their Potential Applications

Contact Info

Product

Resources

About