Control of EOF in CE by different ways of application of radial electric field.

Various ways of application of radial electric field for the control of electrokinetic potential and EOF in a home-made device for CE are presented. The device comprises three high-voltage power supplies, which are used to form a radial electric field across the fused-silica capillary wall. One power supply provides the internal electric field - a driving force for electrophoretic migration of charged analytes and for the EOF.

Evaluation of the efficiency of extraction of ultraviolet-absorbing pollen allergens and organic pollutants from airborne dust samples by capillary electromigration methods.

Capillary electromigration methods, zone electrophoresis (CZE) and micellar electrokinetic chromatography (MEKC), have been used for evaluation of the efficiency of different extraction agents applied to the extraction of pollen allergens and organic pollutants from dust samples collected during different periods (before, during and after pollen seasons) and in different locations in air-filtration devices (car-traffic tunnel in Prague and a metro station in Paris). Water and acetic acid extracts were analyzed by CZE using acetic acid as background electrolyte (BGE). Water and alkaline water-SDS-buffer extracts were analyzed by MEKC in Tris-phosphate BGE with anionic detergent sodium dodecylsulfate (SDS) micellar pseudophase.

External electric field control of electroosmotic flow in non-coated and coated fused-silica capillaries and its application for capillary electrophoretic separations of peptides.

The influence of an external electric field on the electroosmotic flow in the noncoated (bare) fused-silica capillaries and in the fused-silica capillaries with covalent coating of the inner surface by the polymer of a new acrylamido derivative, N-(acryloylaminoethoxy)ethyl-beta-D-glucopyranose, has been tested in the capillary electrophoretic separations of peptide analytes. The effect of magnitude and polarity of the external electric field on the flow-rate of the electroosmotic flow, the migration times of charged analytes and the separation efficiency and resolution of separations of synthetic oligopeptides, diglycine, triglycine, glycyl-proline and prolyl-glycine, by capillary zone electrophoresis has been evaluated. The effect of the external electric field on the velocity of the electroosmotic flow was much higher in the bare fused-silica capillaries than in the coated capillaries.

Capillary zone electrophoresis with electroosmotic flow controlled by external radial electric field.

A new way of regulation of electroosmotic flow (EOF) in capillary zone electrophoresis (CZE) by external electric field has been developed. A set of three high-voltage power supplies is used to form a radial electric field across the capillary wall. One power supply is applied in the usual way as a driving force of CZE and EOF to the ends of the inner capillary compartment dipped into the electrode vessels and filled with background electrolyte.

Theory of the correlation between capillary and free-flow zone electrophoresis and its use for the conversion of analytical capillary separations to continuous free-flow preparative processes. Application to analysis and preparation of fragments of insulin.

A basic theoretical description of the correlation between capillary zone electrophoresis (CZE) and free-flow zone electrophoresis (FFZE) is presented. The theory of the correlation between CZE and FFZE results from the fact that both methods are based on the same separation principle, zone electrophoresis, and both are performed in the carrierless separation medium with the same composition of the background electrolyte. The equations describing the movement of the charged and noncharged particles in the d.

Contribution of capillary coiling to zone dispersion in capillary zone electrophoresis.

A mathematical model of the deformation of the analyte zone in capillary zone electrophoresis (CZE) due to capillary coiling is presented and the influence of capillary coiling on the distribution of electric current density inside the capillary is described. The model gives a quantitative description of the potential contribution of capillary coiling to the total zone dispersion in CZE. The zone broadening caused by capillary coiling is calculated as the difference of migration distances of the particles migrating at the inner circumference of the capillary coil and those migrating at the outer circumference.

Capillary electrophoresis device with double UV detection and its application to the determination of effective mobilities of peptides.

A new experimental device for high-performance capillary electrophoresis (HPCE) with a double UV detection system and with thermostating of the whole separation compartment was developed. UV detection is doubled by producing two apertures placed symmetrically close to the axis of the optical path of the single-beam UV detector and by the adjustment of the capillary loop on these two apertures. The double-detection system allows exact measurements of electrophoretic and electroosmotic flow velocities.

Application of capillary and free-flow zone electrophoresis and isotachophoresis to the analysis and preparation of the synthetic tetrapeptide fragment of growth hormone-releasing peptide.

The use of high-performance electromigration separation methods, capillary zone electrophoresis (CZE) and capillary isotachophoresis (CITP) and continuous free-flow arrangements of these two separation principles, free-flow zone electrophoresis (FFZE) and free-flow isotachophoresis (FFITP), was investigated in the analysis and purification of the synthetic C-terminal tetrapeptide fragment (H2N-Ala-Trp-D-Phe-Lys.NH2) of the growth hormone-releasing peptide. CZE and CITP were used for microanalysis of peptide preparations after different steps of their purification.

Application of capillary isotachophoresis in peptide analysis.

This paper gives a broad and detailed review of the applications of one of the modern high-performance electromigration separation techniques--capillary isotachophoresis (ITP)--in peptide analysis. Examples are presented of the utilization of capillary ITP for peptide analysis in the fields of chemistry, general and clinical biochemistry, biology, biotechnology, pharmacy and the food industry. The complete composition of all the electrolyte systems used for peptide ITP analyses in both cationic and anionic techniques is given in tabular form.

Correlation of capillary zone electrophoresis with continuous free-flow zone electrophoresis: application to the analysis and purification of synthetic growth hormone releasing peptide.

Two carrier-free electrophoretic separation methods, capillary zone electrophoresis (CZE) and continuous free-flow zone electrophoresis (FFZE), have been applied to both microanalysis at the nanogram level and preparative fractionation, with a throughput of 30 mg/h, of synthetic growth hormone releasing peptide (GHRP). A crude product of GHRP, a hexapeptide with the sequence His-D-Trp-Ala-Trp-D-Phe-Lys-NH2, synthesized by the solid phase methodology, was desalted and analyzed by CZE. Based on the results of analytical CZE the separation was converted into a preparative purification procedure by continuous FFZE, employing the same separation medium (0.

Isotachophoretic analysis of peptides. Selection of electrolyte systems and determination of purity.

Capillary isotachophoresis (ITP) was applied to the qualitative and quantitative analysis of both natural and synthetic oligo- and polypeptides. Based on the mathematical model of acid-base equilibria for a general ampholyte, a procedure and a computer program for the calculation of the pH dependence of the effective and specific charge and effective mobility of peptides with known amino acid sequence were developed which allow the selection of electrolyte systems for peptide isotachophoretic analysis to be rationalized. Basic peptides (bovine pancreatic trypsin inhibitor, bull seminal isoinhibitors of trypsin, arginine vasopressin and adamantylamide-alanylisoglutamine) were analysed with a cationic ITP system at acidic pH.

Micropreparative isotachophoretic electrodesorption of monoclonal antibodies from an affinity adsorbent.

The principle of isotachophoretic desorption of proteins from an affinity sorbent was used for the preparative isolation of monoclonal antibodies against transferrin, under a cationic regimen. Electrodesorption was carried out on an apparatus of our own construction with a photometric detector and a detector of potential gradient. The apparatus was provided with a sorption element filled with an exchangeable affinity active sorbent.

Isotachophoretic electrodesorption of proteins from an affinity adsorbent on a microscale.

Cationic isotachophoresis was used for the desorption of mouse monoclonal antibody to transferrin strongly affinity-bonded to transferrin immobilized on polyethyleneglycol terephthalate powder. The electrodesorption under nondestructive conditions was effected in the capillary isotachophoresis apparatus of our own construction which was equipped with an adsorption element. The electrodesorption is on-line connected with quantitative isotachophoretic analysis of the antibody desorbed.

Isolation of human haemopexin by bioaffinity chromatography on haeme-sepharose.

A preparative procedure was developed for the isolation of human apohaemopexin from Cohn fraction IV or blood serum, based on bioaffinity chromatography on haeme-Sepharose. The isolation is carried out in the pH range 4-8; hence the possibility of degradation of the carbohydrate moiety of the glycoprotein in the acidic media used in other isolation procedures is decreased. Owing to the conditions of the separation and the good stability of the affinity support, the column can be used repeatedly for long periods without a significant loss of binding capacity.

Induction of extrajunctional acetylcholine sensitivity of rat EDL muscle by peptidic component of peripheral nerve.

The induction of extrajunctional ACh-sensitivity was studied electrophysiologically 4 days after implantation of segments of the sciatic nerve, segments of dorsal and ventral spinal roots and silastic plates, containing some components of peripheral nerve onto surface fibres of innervated rat extensor digitorum longus muscle. It has been found that extrajunctional ACh-sensitivity can be induced by a piece of rat sciatic nerve and by peptidic material of about 8,000 and 10,000 mol. wt.