Capillary Electrophoresis

Capillary Electrophoresis (CE) performs in a separation channel of elastic quartz capillary under the influence of a high voltage direct current field. Analytes are separated based on differences in mobility and/or distribution behavior of components.

The control of electroosmosis flow (EOF) is important in CE. When the quartz capillary is filled with buffer, the silica hydroxyl group on the tube wall will dissociate and release hydrogen ions into the solution, making the tube wall negatively charged and forming an electrical double layer with the solution. When a DC voltage is applied, the positively charged solution will move towards the negative end as a whole. This overall movement of the solution is called electroosmosis flow. The reproducibility of CE separation will be seriously affected by small changes in EOF. The methods used to control EOF mainly include changing the composition and concentration of the buffer solution, changing the pH value of the buffer solution, adding additives, capillary wall modification, applying a radial electric field, changing the temperature, etc.

Fig.1 Illustration of isoelectric focusing

• Preparation
  Preheat the capillary electrophoresis apparatus and flush the capillary with no voltage applied. Prepare mixed standard samples. Prepare buffer solution.
• Sample Application
  Put the appropriate amount of mixed standard samples in the sample tube at the corresponding position at the inlet of the capillary electrophoresis apparatus, and put the appropriate amount of buffer in the sample tube at the corresponding position of the apparatus.
• Electrophoresis
  Switch on the electrophoresis apparatus and set the voltage and program. Initiate automatic sampling, electrophoresis, and analysis.
• Determination
  Record and analyze the migration of each component. Capillary electrophoresis apparatus can be connected with various detectors to detect the separation. The most widely used is the UV-visible spectrophotometric detector.
  After the experiment, flush the capillary again.

• Better resolution and higher sensitivity
• Online detection
• Less time consumption
• Simple and automatic operation
• Low cost
• Lower sample volume required
• Separation of both uncharged and charged molecules available
• Various separation modes optional

• Simultaneous determination of ions in saliva
• Detection and amplification of DNA fragments
• Detection of microbial and bacterial contamination
• Typing of STR from biological samples
• Quantification of active drugs, determination of impurities in active drugs, pharmaceutical analysis and evaluation of their stability
• Clinical drug analysis, dynamic analysis of absorption, distribution, metabolism and excretion of drugs or metabolites entering human body

Electrophoresis Systems

An electrophoresis system applies an electric charge to molecules, causing them to migrate toward their oppositely charged electrode. It’s the device for electrophoresis performing and is usually divided into horizontal type and suspension type. The choice of electrophoresis systems depends on the molecule of study, the method of separation and the downstream application.

Electrophoresis Accessories

We provide comprehensive electrophoresis accessories including electrophoresis power supplies, combs, UV blocking mats, exposure cassettes, gel cutting tools, short plates, spacer plates, and so on, for gel preparation and electrophoresis performance in electrophoresis experiments.

pH Meters

A pH meter is an instrument used to determine the pH value of a solution, utilizing the relationship between the electromotive force of the galvanic cell and the hydrogen ion concentration. A pH meter is used to determine the pH value of buffers in electrophoresis experiments. The temperature and ionic strength should be considered in pH measurement.

Pipettes

Pipettes are used to aspirate and dispense larger and specific amounts of liquid. They made be reusable or disposable, made from glass or plastic (typically polystyrene), nonsterile, sterile, or autoclavable, and cotton-plugged or plain. Accurate liquid measurements, dilutions, and transfer is key to most successful laboratory assays and analyses.

Spectrophotometers

A spectrophotometer produces a specific wavelength light source through a series of spectrophotometric devices. After the light source passes through the tested sample and is absorbed, the absorption value of the sample is calculated and converted into the concentration of the sample. A spectrophotometer is often used to quantify nucleic acid and protein in electrophoresis experiments.

STEMart provides you with a variety of electrophoresis equipment or consumables to meet your various R&D and application needs. If you have any questions or requirements for capillary electrophoresis, please feel free to contact us.