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Why does paper fluoresce after addition of ethidium bromide - (Jun/23/2015 )

When I image wet chromatography paper in a gel-doc, the intensity is not much. When I add a drop of ethidium  bromide in water (0.5 ug/ml) on this paper, it gives a high intensity. Washing the paper with water does not really decrease the intensity.The same ethidium bromide solution, when imaged in a PCR tube, gives little intensity.  It is clear that what I am seeing is not just paper's autofluorescence. It looks like EtBr binds strongly to cellulose. (1) Does anyone know if this is the case and why? (2) Is there a way to quench the fluroscence of EtBr on paper? Any help will be much appreciated. Thanks a lot.





If you simply need to avoid the fluorescence (as opposed to understanding it) then you could use a membrane (PVDF e.g.). I'd be surprised if your "cellulose" does not have substantial amounts of DNA present.


Thank you for your reply. There is definitely no DNA. From what you say, does PVDF membrane block all kind of fluroscence?