Bromure d’éthiodium UltraPure™, 10 mg/ml

For use in agarose gels:

- Add ethidium bromide to melted agarose to a final concentration of 0.5 µg/mL. Do not melt agarose that already contains ethidium bromide.

For staining agarose gels after electrophoresis:

- You can stain gels that have been run in the absence of ethidium bromide by covering the gel in 0.5 µg/mL ethidium bromide in water and gently agitating for 10 to 30 minutes.
- If necessary, gels can be destained by shaking in H2O for an additional 30 minutes. To stain RNA gels, you should minimize staining time and definitely include a destaining period.

Ethidium bromide can be used to detect ssDNA, RNA, and dsDNA. This fluorescent dye intercalates between the stacked bases of nucleic acids, and exhibits an increased fluorescence at 590 nm. Ethidium bromide can detect down to ~1-10 ng/band of dsDNA in an agarose gel.

After electrophoresis, the gel should be stained in a 0.5-1.0 µg/mL solution of ethidium bromide in deionized water for 15 to 60 min depending on the thickness of the gel. As an optional step to reduce background fluorescence, the gel can be destained in deionized water for 15 to 30 min. Alternatively, ethidium bromide may be added directly to the agarose prior to casting. Add ethidium bromide to melted agarose to a final concentration of 0.5 µg/mL. This has the advantage of reducing the amount of ethidium bromide waste. However, this procedure may reduce the migration rate of nucleic acids.