Thermo Scientific Pierce Polyacrylamide Desalting Columns are ready-to-use, disposable, gel-filtration columns for separating proteins and other macromolecules from low-molecular weight buffer salts and reagents.
Pierce Polyacrylamide Desalting Columns are pre-packed with porous polyacrylamide beads and provide for buffer-exchange and desalting of proteins and other macromolecular samples based on a molecular-weight cutoff (MWCO) of 6000 or 1800. Unlike other size-exclusion media, polyacrylamide resin is not subject to enzymatic degradation and will not serve as a nutrient for microbial growth. The resin is very hydrophilic, thereby minimizing undesirable binding interactions between the resin and sample molecules. Contamination with low molecular weight sugars (which may occur with crosslinked dextran resin) is not a concern when using polyacrylamide resin. Oxidizing agents can be removed without destroying the support. This resin is susceptible to hydrolysis of amide groups under extreme pH conditions, so an operating pH of 2-10 is recommended at room temperature. The polyacrylamide resin can also be autoclaved at pH 5.5-6.5 for 30 minutes at 120°C.
Highlights of Polyacrylamide Resin:
- Stable in water, salt solutions, organic solvents and alkaline or acidic conditions
- Excellent flow properties
- Removing salts from protein solutions
- Removing phenol from nucleic acid preparations
- Separating excess crosslinker from conjugate preparations
- Removing excess derivatizing agents from modified proteins
- Removing unreacted dye from fluorescent antibodies
- Removing free radiolabel from labeled proteins
- Exchanging one buffer for another
The columns rated as having an 1800 molecular-weight cutoff (MWCO) use a resin whose beads have a wet diameter of 45 to 90µm. These columns are ideal for separating peptides and small macromolecules (greater than 1.8kDa) from buffer salts and other compounds (less than 500 MW). The 6K MWCO columns are suitable for proteins and molecules greater than 6kDa.
Gravity-flow resin filtration involves the chromatographic separation of molecules of different dimensions based on their relative abilities to penetrate into a suitable stationary phase. A chromatographic matrix, usually consisting of very small, uncharged porous particles in an aqueous solution, is packed into a column and then used for the separation. Different levels of separation can be achieved based on the pore size of the medium packed into the column. The medium can be chosen to totally exclude proteins or large molecules, while still including small solutes. Large molecules are excluded from the internal pores of the resin and emerge first from the column. The smaller molecules are able to penetrate the pores, then progress through the column at a slower rate. These smaller molecules are subsequently flushed through the column with additional buffer volume.
Desalting and buffer exchange are two of the most widely used applications of resin filtration chromatography.
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