Ambion® formamide has been deionized, is nuclease-free and comes packaged as a liquid in an amber glass bottle under argon. Supplied in one bottle containing 500 g each.Formamide lowers the melting temperature of nucleic acid duplexes and is widely used in applications such as Southern and northern blotting, nuclease protection assays, S1 mapping, and in situhybridization. For critical applications, it is recommended that the formamide from previously opened bottles be deionized before use.