OD reading - (Feb/04/2010 )

does anybody know what it means if we get RNA OD reading at 260/280 = 1.5 but the concentration was
-0.56ug/ml. i'm extracting RNA from cryopreserved bull sperm by using Rneasy mini kit from Qiagen..

faiz on Feb 4 2010, 05:25 AM said:

i am only a bit experienced in RNA extraction, but from what i know, OD 260 gives you the density of nucleic acids (RNA+DNA), and OD 280 detects proteins. the ratio 260/280 then tells you whether your sample is not 'clean' and still contains proteins.
normally you should get a ratio 260/280 above 2 for 'clean' samples (2-fold more nucleic acids than proteins). here your ratio is 1.5, meaning that you still have lots of proteins in your sample.
the concentration of nucleic acids shows that you don't have any nucleic acid in your sample!
lilie22