RNA gel electrohoresis - (Nov/18/2009 )

Kindly let me know as to why do we need to use both formamide as well as formaldehyde during the RNA separation by agarose gel electrophoresis-I know that they are used as denaturants-but why both and why not just one of them?
thanks in advance

depends on which protocol you are following.

formaldehyde is used in the gel.

you use either formaldehyde or formamide in the sample buffer.