What contaminant in my oligo can give an absorption peak at 240-245 nm?

11 November 2013 1 1K Report

I have a modified DNA oligo that started giving me trouble with ligations. Upon running it on nanodrop, I saw a strange peak at 240-245 nm along with one at 280 nm. I don't know what this peak could be and knowing potential contaminants might help me clean the oligo up since it is precious and cannot be discarded or remade. The oligo was dissolved in nuclease free water and stored at -20.

Juan Feng

I have the same problem with you. I get the 240mm peak after DNA gel extraction. the DNA concentration is 20ng/ul.

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