LIVIVO - The Search Portal for Life Sciences

zur deutschen Oberfläche wechseln
Advanced search

Search results

Result 1 - 4 of total 4

Search options

  1. Article: Conductivity detection and quantitation of isotachophoretic analytes on a planar chip with on-line coupled separation channels.

    Masár, M / Zúborová, M / Bielcíková, J / Kaniansky, D / Jöhnck, M / Stanislawski, B

    Journal of chromatography. A

    2001  Volume 916, Issue 1-2, Page(s) 101–111

    Abstract: A poly(methylmethacrylate) chip, provided with two separation channels in the column-coupling (CC) arrangement and on-column conductivity detection sensors and intended, mainly, to isotachophoresis (ITP) and ITP-capillary zone electrophoresis (CZE) ... ...

    Abstract A poly(methylmethacrylate) chip, provided with two separation channels in the column-coupling (CC) arrangement and on-column conductivity detection sensors and intended, mainly, to isotachophoresis (ITP) and ITP-capillary zone electrophoresis (CZE) separations was developed recently. The present work was aimed at assessing its performance relevant to the detection and quantitation of the ITP analytes. Hydrodynamic (HDF) and electroosmotic (EOF) flows of the solution in the separation compartment of the CC chip were suppressed and electrophoresis was a dominant transport process in the ITP separations with model analytes carried out in this context. When the surfaces of the detection electrodes of the conductivity sensors on the chip were appropriately cleaned qualitative indices of the test analytes [relative step heights (RSHs)], provided by a particular detection sensor, agreed within 1% (expressed via RSDs of the RSH values). Their long-term reproducibilities for one sensor, as estimated from 70 ITP runs repeated in 5 days, were 2% or less. Sensor-to-sensor and chip-to-chip fluctuations of the RSH values for the test analytes were 2.5% or less. In addition, experimentally obtained RSH values agreed well with those predicted by the calculations based on the ITP steady-state model. Reproducibilities of the migration velocities attainable on the CC chips with suppressed EOF and HDF, assessed from the migration time measurements of the ITP boundary between well-defined positions on the separation channels of the chips (140 repeated runs on three chips), ranged from 1.4 to 3.3% for the migration times in the range of 100-200 s. Within-day repeatabilities of the time-based zone lengths for the test analytes characterized 2% RSDs, while their day-to-day repeatabilities were less than 5%. Chip-to-chip reproducibilities of the zone lengths, assessed from the data obtained on three chips for 100 ITP runs, were 5-8%.
    MeSH term(s) Electrochemistry ; Electrophoresis/methods ; Reproducibility of Results ; Semiconductors
    Language English
    Publishing date 2001-05-04
    Publishing country Netherlands
    Document type Journal Article ; Research Support, Non-U.S. Gov't
    ZDB-ID 1171488-8
    ISSN 1873-3778 ; 0021-9673
    ISSN (online) 1873-3778
    ISSN 0021-9673
    DOI 10.1016/s0021-9673(00)01236-x
    Database MEDical Literature Analysis and Retrieval System OnLINE

    More links

    Kategorien

  2. Article: Zone electrophoresis of proteins on a poly(methyl methacrylate) chip with conductivity detection.

    Zúborová, Mária / Demianová, Zuzana / Kaniansky, Dusan / Masár, Marián / Stanislawski, Bernd

    Journal of chromatography. A

    2003  Volume 990, Issue 1-2, Page(s) 179–188

    Abstract: This work deals with zone electrophoresis (ZE) separations of proteins on a poly(methyl methacrylate) chip with integrated conductivity detection. Experiments were performed in the cationic mode of the separation (pH 2.9) with a hydrodynamically closed ... ...

    Abstract This work deals with zone electrophoresis (ZE) separations of proteins on a poly(methyl methacrylate) chip with integrated conductivity detection. Experiments were performed in the cationic mode of the separation (pH 2.9) with a hydrodynamically closed separation compartment and suppressed electroosmotic flow. The test proteins reached the detector in less than 10 min under these working conditions and their migration times characterized excellent repeatabilities (0.1-0.6% RSD values). The chip-to-chip agreements of the migration times, evaluated from the ZE runs performed on three chips, were within 1.5%. The conductivity detection provided for protein, loaded on the chip at 10-1000 microg/ml concentrations, detection responses were characterized by 1-5% RSD values of their peak areas. Such migration and detection performances made a frame for reproducible baseline separations of a five-constituent mixture (cytochrome c, avidin, conalbumin, human hemoglobin and trypsin inhibitor). On the other hand, a high sample injection channel/separation compartment volume ratio of the chip (500 nl/8500 nl) restricted the resolution of proteins of very close effective mobilities in spite of the fact that in the initial phase of the separation an electric field stacking was applied. A maximum macroconstituent/trace constituent ratio attainable for proteins on the chip was assessed for cytochrome c (quantifiable when its concentration in the loaded sample was 10 microg/ml) and apo-transferrin (containing a trace constituent migrating in the position of cytochrome c detectable when the load of apo-transferrin was 2000 microg/ml). This assessment indicated that a ratio of 1000:1 is attainable with the aid of conductivity detection on the present chip.
    MeSH term(s) Electric Conductivity ; Electrochemistry ; Electrophoresis/instrumentation ; Polymethyl Methacrylate/chemistry ; Proteins/isolation & purification
    Chemical Substances Proteins ; Polymethyl Methacrylate (9011-14-7)
    Language English
    Publishing date 2003-03-21
    Publishing country Netherlands
    Document type Journal Article ; Research Support, Non-U.S. Gov't
    ZDB-ID 1171488-8
    ISSN 1873-3778 ; 0021-9673
    ISSN (online) 1873-3778
    ISSN 0021-9673
    DOI 10.1016/s0021-9673(02)01805-8
    Database MEDical Literature Analysis and Retrieval System OnLINE

    More links

    Kategorien

  3. Article: Determination of oxalate in urine by zone electrophoresis on a chip with conductivity detection.

    Zúborová, Mária / Masár, Marián / Kaniansky, Dusan / Jöhnck, Matthias / Stanislawski, Bernd

    Electrophoresis

    2002  Volume 23, Issue 5, Page(s) 774–781

    Abstract: The use of a poly(methylmethacrylate) capillary electrophoresis chip, provided with a high sample load capacity separation system (a 8500 nL separation channel coupled to a 500 nL sample injection channel) and a pair of on-chip conductivity detectors, ... ...

    Abstract The use of a poly(methylmethacrylate) capillary electrophoresis chip, provided with a high sample load capacity separation system (a 8500 nL separation channel coupled to a 500 nL sample injection channel) and a pair of on-chip conductivity detectors, for zone electrophoresis (ZE) determination of oxalate in urine was studied. Hydrodynamic and electroosmotic flows of the solution in the separation compartment of the chip were suppressed and electrophoresis was a dominant transport process in the separations performed on the chip. A low pH of the carrier electrolyte (4.0) provided an adequate selectivity in the separation of oxalate from anionic urine constituents and, at the same time, also a sufficient sensitivity in its conductivity detection. Under our working conditions, this anion could be detected at a 8 x 10(-8) mol/L concentration also in samples containing chloride (a major anionic constituent of urine) at 3.5 x 10(-3) mol/L concentrations. Such a favorable analyte/matrix concentration ratio (in part, attributable to a transient isotachophoresis stacking in the initial phase of the separation) made possible accurate and reproducible (typically, 2-5% relative standard deviation (RSD) values of the peak areas of the analyte in dependence on its concentration in the sample) determination of oxalate in 500 nL volumes of 20-100-fold diluted urine samples. Short analysis times (about 280 s), no sample pretreatment (not considering urine dilution) and reproducible migration times of this analyte (0.5-1.0% RSD values) were characteristic for ZE on the chip. This work indicates general potentialities of the present chip design in rapid ZE analysis of samples containing the analyte(s) at high ionic matrix/analyte concentration ratios.
    MeSH term(s) Electric Conductivity ; Electrophoresis, Capillary/methods ; Humans ; Microchemistry/methods ; Oxalates/urine ; Polymethyl Methacrylate
    Chemical Substances Oxalates ; Polymethyl Methacrylate (9011-14-7)
    Language English
    Publishing date 2002-03
    Publishing country Germany
    Document type Journal Article ; Research Support, Non-U.S. Gov't
    ZDB-ID 619001-7
    ISSN 1522-2683 ; 0173-0835
    ISSN (online) 1522-2683
    ISSN 0173-0835
    DOI 10.1002/1522-2683(200203)23:5<774::AID-ELPS774>3.0.CO;2-G
    Database MEDical Literature Analysis and Retrieval System OnLINE

    More links

    Kategorien

  4. Article: Electrophoretic separations on chips with hydrodynamically closed separation systems.

    Kaniansky, Dušan / Masár, Marián / Bodor, Róbert / Žúborová, Mária / Ölvecká, Eva / Jöhnck, Matthias / Stanislawski, Bernd

    Electrophoresis

    2003  Volume 24, Issue 12-13, Page(s) 2208–2227

    Abstract: This review focuses on capillary electrophoretic separations performed on capillary electrophoresis chips (CE chips) with hydrodynamically closed separation systems in a context with transport processes (electroosmotic flow (EOF)) and hydrodynamic flow ( ... ...

    Abstract This review focuses on capillary electrophoretic separations performed on capillary electrophoresis chips (CE chips) with hydrodynamically closed separation systems in a context with transport processes (electroosmotic flow (EOF)) and hydrodynamic flow (HDF)) that may accompany the separations in these devices. It also reflects some relevant works dealing with conventional CE operating under such hydrodynamic conditions. The use of zone electrophoresis (ZE), isotachophoresis (ITP) and their on-line combination (ITP-ZE) on the single-column and column-coupling CE chips with the closed separation systems and related problems are key topics of the review. Some attention is paid to sample pretreatment in the separations performed on the CE chips. Here, mainly potentialities of the ITP-ZE combination in trace analysis applications of the miniaturized systems are discussed in a broader extent. Links between the ZE separation and detection provide a frame for the discussion of current status of the detection on the CE chips. Analytical applications illustrate potentialities of the CE chips operating with the closed separation systems (suppressed HDF and EOF) to the determination of small ions present in various matrices by ZE, ITP and ITP-ZE.
    MeSH term(s) Electrophoresis, Capillary/instrumentation ; Electrophoresis, Capillary/methods ; Semiconductors
    Language English
    Publishing date 2003-06
    Publishing country Germany
    Document type Journal Article ; Research Support, Non-U.S. Gov't ; Review
    ZDB-ID 619001-7
    ISSN 1522-2683 ; 0173-0835
    ISSN (online) 1522-2683
    ISSN 0173-0835
    DOI 10.1002/elps.200305474
    Database MEDical Literature Analysis and Retrieval System OnLINE

    More links

    Kategorien

To top