miRNA from plasma_purity problem after RNA isolation - (Jun/05/2012 )

Dear All,

I am working on plasma miRNAs. I'm trying to isolate miRNA from plasma with Qiagen miRNeasy Mini Kit. I usually got ~10-20ng/mkl (Nanodrop), but the 260/230 ratio is awful (0,15-0,4) and 260/280 is also around 1,5-1,6. It seems to be, that the contamination is phenol (Trizol). For qRT-PCR it is okey, working really nice, but I afraid, for microarray it is too contaminated.

Anybody know how can I clean my samples (to get rid of phenol)? Anybody tried it?

Thanks a lot!

It's GuSCN that causes the super low 260/230, because even trace amount of GuSCN has stronge absorption at 230. But it would not likely affect your downstream applications, including microarray.