Isopropanol precipitatation overnight - (Oct/05/2011 )
During DNA precipitation i always incubate it in isopropanol overnight at 4oC, and instead of getting a nice pallet of DNA my DNA either be in goo form or jelly form. Is there any different between precipitate DNA for a couple hour in room temp and doing it overnight at 4oC. If there is whats is the reason.
IPA pellets are often gel like. It doesn't really matter which temperature you ppt at, the amount of extra DNA (or RNA) you manage to precipitate is minimal.
thanks bob1 =)
What about the time period then, will it effect the yield of DNA.
In theory yes, in practice, not really - you might be able to squeeze a few extra micrograms out, but it also increases the risk of precipitating any extra proteins or RNA that are still there.
What happen to my DNA is that, after kept in -20 it tend to be gel-like and i can actually spins down the gel and collect the solution above it. When i measure the OD of the solution i can still get a good yield of DNA. AS for the gel i'm not sure whether it is DNA, protein or salt.
oh, and the purity is way below 1.8 (A260/280)