MicroSpin G-25 columns contain Sephadex G-25 DNA Grade F resin. They allow DNA purification via gel filtration. Gel filtration resins do not exhibit a fixed exclusion limit when used in a spin-column format. In spin-column chromatography, the observed exclusion properties that allow the product to pass through the gel while the smaller impurities are retained depends on experimental factors. These factors include the resin used, sample volume, product size, and the g-forces used.

The resin used in these columns, Sephadex G-25 has an exclusion limit of approximately Mr 5000. With a spin protocol this resin can be used for any DNA greater than 10 bases in length.

Sephadex G-25 is one of five different G-types ranging from G-10 for small molecules to G-100 for larger molecules. Sephadex G-50 is a well-established gel filtration resin for desalting and buffer exchange of biomolecules >30 000 molecular weight, and with a spin protocol can be used for DNA and oligo purification of molecules greater than 20 bases in length. Sephadex G-100 DNA Grade has an exclusion limit of 25bp ds DNA.

All these Sephadex types are therefore highly suitable for the purification of oligonucleotides or small DNA fragments following synthesis or labeling reactions.

Sephadex G-25, G-50 DNA Grade and Sephadex G-100 are all sold separately.