34 results about "IEF - Isoelectric focusing" patented technology

Described herein is a method and system for on-line coupling of capillary isoelectric focusing (cIEF) to high-resolution mass spectrometry in which a sheath flow buffer comprising polar organic solvent and organic acid is used as both an immobilization solution for (cIEF) and an ionization solution for electrospray ionization (ESI).

A specified proton concentration in a volume (80) is produced by passing a controlled electrophoresis current through an adjacent electrophoresis volume (28) between a working electrode (26) and a counter electrode (24). An array of such volumes with specified proton concentration is used to provide the pH gradient for isoelectric focusing.

Described herein is a method and system for on-line coupling of capillary isoelectric focusing (cIEF) to high-resolution mass spectrometry in which a sheath flow buffer comprising polar organic solvent and organic acid is used as both an immobilization solution for (cIEF) and an ionization solution for electrospray ionization (ESI).

An elastomeric cell is used as the disposable part of an apparatus for isoelectric focusing in free solution (without gels) in the 0.5 to 5 ml volume range. An inlet port is used for priming the cell and end-connectors for coupling with electrodes. A grid of parallel rods compresses the cell against a cold plate, thereby causing swelling of the skin of the cell between pairs of rods and forming contiguous fluid bubble-compartments for IEF separation. Before collection of separated fractions, the gap between the rods and the plate is further reduced so as to create distinct fluid compartments which now contain discrete products of separation. The separated fractions are collected by syringe-like devices by puncturing the elastomer skin. The plate, rods and deformable cell are capable of rotation or gentle rocking motion around the cell's main axis to avoid gravitational convection during the focusing process.

The invention discloses a polypeptide mixture isoelectric focusing separation method for proteomics analysis. The method comprises the following steps: performing restriction enzyme digestion on a total protein mixture of a biological sample completely to obtain relatively short peptide fragment mixtures; re-dissolving the peptide fragment mixtures by using a peptide fragment isoelectric focusing buffer solution; performing isoelectric focusing electrophoresis in a loading manner by adopting a loading cup, so as to realize the effective separation of a complex peptide fragment mixture; performing desalination on a taken polypeptide mixture pre-separated from each groove and performing mass spectrometry analysis so as to obtain more polypeptide signals, higher peptide fragment covering rate and higher protein identification number compared with those obtained when a conventional method is adopted. The method is precise, efficient and low in cost, can be used in multidimensional liquid chromatography-mass spectrum identification technology systems of total proteins of the various biological samples, can replace a conventional ion exchange chromatography pre-separation method so as to realize the efficient pre-separation of the peptide fragment mixtures, and avoids the lost of peptide fragments, and therefore, proteome expression profile information with the high covering rate can be established.

A multiplexed, absorbance-based microfabricated chip electrophoresis system, microfabricated chip, and method of use are included for the detection and identification of protein species. The microfabricated chip electrophoresis system capable of analyzing multiple samples simultaneously. The system uses a microfabricated chip having a sample chamber for first dimension separation of a sample, a first planar array of channels for second dimension separation of the sample approximately perpendicular the sample chamber, and a barrier separating the sample chamber from the first planar array of channels during the first dimension separation. In use, the sample is placed into a sample chamber, a barrier is established around the sample chamber, the sample is isoelectric focused within the sample chamber, the barrier is then removed, and the sample separated in the first array of channels by molecular weight.

The invention relates to a microfluidic chip, particularly to a microfluidic chip for isoelectric focusing separation, which is provided with two substrates that are bonded in reversible or non-reversible way, wherein a micro-channel and an access hole are machined in one substrate; the access hole serves a liquid storage tank; the micro-channel is provided with an extracting area and an expanding area; a transitional connecting area is arranged between the extracting area and the expanding area; and the connecting area is provided with an inclination angle. Under the premise that the pH gradient is a set value, the cyclical variation of the width of the micro-channel is utilized to enable the electric field distribution in the micro-channel to regularly vary, so as to form the non-linear pH gradient, as a result, the protein samples with similar isoelectric points can be separated in higher resolution. The microfluidic chip has the characteristics that the microfluidic chip has small size, saves reagent, is quick to separate, is convenient for integration and automation, can machine thousands of repeated micro-structures once for all, has low cost, is simple and convenient to make and operate, has high efficiency, and has excellent effect and practical significance in the isoelectric focusing separation.

A device for fluid phase electrophoresis, particularly solution phase isoelectric focusing, components thereof, and methods for use are presented.

An apparatus and method are disclosed for the precise selection and extraction of a selected analyte in a focused zone produced by isoelectric focusing performed in micro-channels. A cross-channel microfluidic device comprises a sample mixture introduction and separation channel and an extraction channel, which are in fluid communication with each other at a point of intersection. Means are provided for selectively moving the pattern of separated zones following cIEF to the intersection point, and means are provided for applying an extraction pressure to direct a single zone containing a selected analyte into and then out of the extraction channel for collection.

The present invention discloses a method for controlling electroosmotic flow in capillary isoelectric focusing electrophoresis and its equipment. It is characterized by that it adopts freeze method to freeze local fluid in the capillary to make focusing of fluid, then adopts the method of heating capillary to defreeze the solid mobile phase in the capillary and restore the transmission of fluid in the capilalry, so that the flowing-out of the sample can be batch implemented, and the focusing effect of the capillary isoelectric focusing electrophoresis can be greatly raised, and the flowing form in the column is wedge-shaped, and its separation effect is good. On the proper position of capillary separation column a heating device and a freezing device are set.

The invention provides a method for improving experiment accuracy by an isoelectric focusing method of two-dimensional protein electrophoresis, in particular a method for calculating electric energy needed by salt and protein focusing by measuring electric conductivity of a protein object to be measured. The method is characterized in that: electric energy needed by the protein focusing and salt mobility is calculated through a group of formulas in environments of different electric conductivities of the salt, the protein weight, the pH gradient gel length and the range of the pH value respectively, proper electric energy of the experiment of the individual protein object to be measured can be provided in the isoelectric focusing method so as to present an optimal protein focusing result,and the influence of colloidally protein focusing due to insufficient or over-high electric energy is avoided.

An improved method of separating a macromolecule by isoelectric focusing comprising subjecting the macromolecule to electrophoresis in an isoelectric-focusing medium including a substantially thiol-free reducing agent, preferably a trivalent phosphorous compound and more preferably tributyl phosphine, the improvement being the solubility and focusing of the macromolecule is enhanced compared to isoelectric focusing of the same macromolecule in a similar isoelectric-focusing medium containing a thiol-reducing agent.

The invention relates to a method for detecting microorganism isoelectric point by adopting immobilized pH gradient capillary isoelectric focusing (CIEF), belonging to the field of bioanalysis. The method comprises the steps of: firstly carrying out isoelectric focusing on carrier ampholyte solution by adopting constant voltage in a capillary to lead ampholyte with continuous pH gradient to be formed on the inner wall of the capillary; secondly injecting sample solution to the capillary and carrying out isoelectric focusing by adopting the continuous voltage; then adopting immobilized atmospheric pressure to push the sample from focusing section inside the capillary to pass a detecting window at equal speed so as to determine focus point position of the sample; and finally figuring out pHvalue of the focus point according to linear relation between the pH gradient and the length of the capillary. The method can be applied to the simultaneous online detection of various microorganismsand has universality for microorganism isoelectric point detection.

The invention discloses a reciprocating type free flow isoelectric focusing electrophoresis device and a reciprocating type free flow isoelectric focusing electrophoresis method. The reciprocating type free flow isoelectric focusing electrophoresis device is mainly composed of a separation chamber, a liquid storage pipe, a gas liquid buffering chamber, collection pipes, recycling pipes which are located below the collection pipes and correspond to the collection pipes one by one, and a medium driving pump, wherein a separation chamber liquid outlet of the separation chamber is connected with the collection pipes and the recycling pipes respectively by switches; the liquid storage pipe is connected with a gas liquid buffering chamber liquid outlet; the gas liquid buffering chamber liquid outlet is connected with the separation chamber liquid outlet; and the medium driving pump drives media to flow in or out of the gas liquid buffering chamber from the gas liquid buffering chamber liquid inlet. According to the device and the method, one single-path driving pump is used for replacing a multi-channel driving pump; the rapid reciprocating of CA (Carrier Ampholytes) buffering liquid and a sample is used for replacing unidirectional circulation in the prior art by the separation chamber, so that the same effect of an existing RFFIEF technology is achieved; and the technology, equipment and method of the whole ReFFIEF technology are greatly simplified and the cost is reduced.