Help! RNA contamination in my extraction.

[haohao]

Hi everyone,

I have some problems removing the RNA during my phage DNA extraction. I had used 100ul of 10mg/ml of RNAse A prepared in Trish-HCl, pH 7.5 in 1ml of my sample ( is it enough?), and incubated the mixture at 37C for 2 hours, before going into phenol-chloroform-isoamyl alcohol (25:24:1) extraction. However, I'm still observing RNA in the gel electrophoresis. Can anyone provide me some idea how I can improve the activity of the RNaseA or there maybe something wrong with what I am doing? By the way, my sample contains PEG 8000 (for phage precipitation), will that affect the activities of the enzymes?

Thousand thanks for helping me out. Really appreciate it.

Haohao