Dialysis

Dialysis is a process where substances in solution are separated by their differences in molecular weight. The dialysis tubings are semipermeable, made of regenerated cellulose or cellulose ester having a gel-like structure. The driving force is the concentration difference between 2 solutions on opposite sides of the membrane. Since the porous membrane selectively allows smaller solutes to pass while retaining larger species, dialysis can effectively be used as a separation process based on size rejection.

Since the dialysis membrane consists of a spongy matrix of crosslinked polymers, the pore rating referred to as Molecular Weight Cut Off (MWCO), is an indirect measure of the retention performance. The membrane MWCO is determined as the solute size that is retained by at least 90 %. However, since a solute’s permeability is also dependent upon molecular shape, degree of hydration, ionic charge and polarity, it is recommended to select a MWCO that is half the size of the MW of the species to be retained and/or twice the size of the MW of the species intended to pass through.

For many years, dialysis has been successfully used as a routine method for desalting and concentration of complex biomolecules in solution. In addition, macromolecules, differing substantially in molecular weight can be separated.

Applications

  • Desalting of protein solutions, e.g. for further purification by ion exchange chromatography
  • Concentration of protein solutions by embedding the filled tubing in dry PEG 20000 (cat. no. 33138) e.g. before further separation by gel permeation chromatography
  • Separation of high molecular weight proteins from low molecular weight peptides and other substances
  • Buffer exchange with solutions of proteins or other macromolecules
  • Desalting of metallo colloids


News

New !

SERVA Catalog
2019

Product of the Month January:

SERVA HiSens Stain G

Certificates of Analysis
now online!

Western Blotting -
New Brochure!

Top
Close window
New !

SERVA Catalog
2019

In detail you will find the following new products in catalog 2019:

  • • SERVA TAE Clear G Agarose tablets for practical nucleic acid electrophoresis
  • • Novel enzymes such as recombinant PNGases F as lyophilized powder
  • • High-performance protein A/G magnetic agarose beads
  • • New buffers for molecular and cell biology
  • • SERVA BluePower® power supplies running from 300 Volt to 6000 Volt and from 150 mA to 2 A for gel electrophoresis and blotting
  • • Electrophoresis gel and blot automation: SERVA BlueStain is an innovative device for the treatment of automated gel and blot staining
SERVA Catalog 2019.pdf
Close window
Product of the Month January:

SERVA HiSens Stain G

A fluoresecent dye for nucleic acids

→ This way to the Special Offer

Close window
Certificates of Analysis
now online!

How to find the required certificate of analysis for your product:
In the search, enter the 5-digit article number without additional packaging, i.e. 11404 if you are looking for the AZ for your 500 g-Pack Agarose 11404.02.
Now click on the search result and you will be taken to the product entry. Here you will find the link "Certificate of Analysis", which you follow.
Now select the lot number from the list and download the PDF with a click. Done.

Close window
Western Blotting -
New Brochure!
  • • Molecular Weight Standards
  • • SDS PAGE for Western Blotting
  • • Transfer Membranes and Buffers
  • • Blocking Reagents
  • • Detection Systems
  • • Instruments for Western Blotting
SERVA Brochures: Western Blotting V1806 (pdf)
Close window
SERVA - now on YouTube

SERVA InfoMail - Get the latest information

Close window

When subscribing to »SERVA InfoMail« you will receive information about the latest product release, special promotions, new jobs at SERVA and more. This service is, of course, free of charge.
You may remove your name any time from the list of recipients.

Quick Order

Close window

Using the Quick Order field, you can add a product to your shopping cart with just one click. All you have to do: enter the Cat.No. as shown in our catalog in the format xxxxx.yy and click the Go!-Button.