RNA quality from total blood - (Dec/12/2006 )

Hi there!

I'd extracted total RNA from blood sample, and when I've check it quality, I notice that my RNA wasn't good - OD 260/230 between 0.5-1.0.
I am using TRIzol reagent for RNA isolation, so I would like to know what should I do to increase my RNA quality? Does a chloroform wash following RNA isolation (aqueous phase from organic phase) really work well?

Please, does anyone could help me?

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With Trizoll reagent i always find a bad ratio of OD 260/230, too! For example: 2 total microgram of RNa gave me OD260/280 of 1,8 and OD260/230 of 0,6.
But I think it depends also on the total RNA quantity; however Invitrogen says that from Blood, Trizoll reagent is not the good choice! It is usefull extract RNA with column system!

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well i use trizol for a while and my 260/230 are always playing with 2

are you sure that :

• you don't pipett phenolic phases
• you wash efficiently with ethanol 70 to get rid of salts
• you dry your RNA pellet enough

For a 50µl RNA prep, try butnol precipitation like this
add 1ml BuOH.
Homogenize well by handshaking (avoid vortex) till you see a clear solution
pellet 1' 2000rpm
you should see a pellet or a least kind of a bubble which represents the aqueous phase.
So pipett the BuOH (upper) and redo the procedure.
If you see a clear pellet, spin without pipetting the buOH by 12000g at least for 5' (attach better the pellet)
then do 2 washes by EtOH 70%

the butanol is very hydrophobic so it can efficiently pellet all nucleic acids
on the other hand, it needs to enhance washes by 70%EtOH

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Thanks, apemaia and fred_33! I'll try BuOH precipitation and check it out. Thanks!
Another question: I have some RNA samples with these bad OD 260/230 rates; is there something I can do to recover them?

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Just clean the samples up using a column

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but you'll loose sample and it's more expensive. as the ratios 260/280 doesn't seem to be an issue here, BuOh is ok i think

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Thanks again you all!

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