Decontamination of Dilute Solution of Ethidium Bromide

e.g. electroforesis buffer containing 0.5 ug/ml of ethidium bromide (EtBr)

Method 1 (Lunn and Sansone 1987)

1. Add 2.9 g of amberlite XAD-16 for each 100 mL of solution. Amberlite XAD-16, a nonionic, polymeric absorbent, is available from Rohm and Haas.
2. Store the solution for 12 hours at room temperature, shaking it intermitently.
3. Filter the solution through Whatman No.1 filter, and discard the filtrate.
4. Seal the filter and Amberlite resin in a plastic bag, and dispose of the bag in the hazardous waste.

Method 2 (Bensaude 1988)

1. Add 100 mg of powdered activated charcoal for each 100 mL of solution.
2. Store the solution for 1 hour at room temperature, shaking it intermitently.
3. Filter the solution through a whatman No.1 filter and discard the filtrate.
4. Seal the filter and activated charcoal in a plastic bag and dispose of the bag in the hazardous waste.

Notes:

1. Treatment of dilute solutions of EtBr with Hypochlorite (bleach) is not recommended as a method of decontamination. Such treatment reduces the mutagenic activity af EtBr in the Salmonella/microsome assay by about 1000-fold, but it converts the dye into a compound that is mutagenic in the absence of microsomes (Quillardet and Hofnung 1988)
2. EtBr decomposed at 262 Celcius and is unlikely to be hazardous after incineration under standar condition.
3. Slurries of amberlite XAD-16 or activated charcoal can be used to decontaminate surfaces that become contaminated by EtBr.