I was wondering if anyone has come across issues with 260/230 ratios when extracting DNA from a range of mouse tissues using the Sodium Iodide method.
My protocol works well when testing on liver samples with 260/230 ratios of ~2.
However, when I test other tissue types e.g. digestive tract, lung, heart, fats and muscle, I get low readings of 260/230 (ranging from 1.4-1.8, sometimes as low as 1).
I don’t believe the issue is contamination related as the liver samples work perfectly using the same protocol.
The 260/280 ratios are fine at 1.8 for all tissues (except muscle which I am having more problems with)
Thank you for your response and your help Thomas Hartinger
I am using the same protocol for all tissues and the protocol is an in-house protocol (not using any column based kits). I am wondering if there should be slight changes for each tissue? e.g. digestion stages maybe but I am a bit unsure.
I am going to measure 8-OHdG, a marker of DNA oxidation, and that is why I specifically have to use the sodium iodide method. I have been advised that low purity can lower the 8-OHdG measurement with the kits I will use.
My 260/280 ratios are always fine, so do you think I don't have to worry so much about the 260/230 ratios? I really would like to get them improved because of my next steps with the samples!
Thank you again!
I have run some more test samples today with increased volumes of protease (as I thought the digestion stage might be an issue) and it seems to have helped!
I might try increased lysis buffer vol with the range of other tissues I have to do as well.
I have 2 x 70% ethanol washes and another wash didn't help - so along with this and the liver samples working I'm convinced it's not a contamination related issue.
I haven't tested them on the 8-OHdG yet but that's something I plan to do
Thank you for your help!
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