Blue fluorescent color of agarose gel in UV - (Feb/14/2013 )

In our lab we observed a strange thing. My colleague ran a gel and tried to see in UV illuminator. She saw a complete blue background and very faint DNA bands. We thought she has done something wrong. just for reference we checked some old gel, which was dried, and this gel showed blue fluorescence in UV, why it happened any idea? I am attaching the picture of the gel.

Probably contamination of the gel with something that fluoresces, gels do fluoresce a bit anyway.

yes bob, you are right that gels do fluoresce a bit, but since it was not usual. we checked other things like white paper under uv. and it showed the same fluorescence. I checked on google and found out that few colors like white, pink etc do glow under uv. But still no idea about why gel showed the same kind of fluorescence as a white paper gave

Someone accidentally put tissue in the gel buffer? This usually shows up as flecks in the gel though. There are a number of compounds that will fluoresce blue, most of the common ones are plant related.

I would remake the gel with fresh buffer and see if the problem goes away.

Could it be the lense(s) through which you are viewing it was/were altered in some way? I vaguely remember seeing blue throughout a gel (w/ no red or orange) under UV illumination once, and for some reason I'm thinking that was the case... but I really don't remember.

No, the lens seems to work fine. But we will check again and get back here.

Has someone switched from long wave to short wave UV illumination? Many imagers can do either, and short wave can fluoresce things that you don't expect to fluoresce. There is a big difference between 254, 312, and 365 nm illumination.

No phage it was same UV wavelength. Anyways we haven't checked any gel on illuminator after this. I hope somebody will be doing this week, we'll check again.