A New Method for the disposal of Ethidium Bromide waste
Ethidium Bromide
Ethidium Bromide (EtBr) is used to visualize DNA bands separated by electrophoresis.
The EtBr is inserted between double stranded DNA chains,
and therefore has a potent mutagens and carcinogens. Processing completely the waste fluid after using the dye is necessary.
Conventional Methods
A common practice to dispose of the EtBr waste is to mix dilute solutions with the hypochlorite (bleach) .
Such a process converts Ethidiumbromide into an even more mutatagenic substance.
Therefore, this method is not recommended now.
Now, an adsorption method using the activated charcoal, or a polymeric resin
such as Amberlite XAD-16 is used for disposing of EtBr waste.
However, we cannot know whether the EtBr waste was completely treated.
The most importance for processing of dangerous substrates is validation that it is completely fulfilled.
These conventional methods are No!
Adsorption to activated charcoal
Adsorption to resin
Chemical deactivation
Filtration
Bag
Column
Tea bag
Decomposition
A New Method : Adsorption with Zero Column
A new method is quite different from the conventional one, which is not anywhere all over the world.
Adsorbent is consisted of Okara and cellulose fibers.
Okara is a by-product in soybean food manufacturing such as Tofu, soy bean curd.
Okara as the adsorbent is held in the matrix of the cellulose fibers.
EtBr is adsorbed on soybean protein called glycinin in Okara with a hydrophobic bond.
The color of EtBr waste is light red, and the color of the column gradually changes into deep red by adsorption of EtBr.
Therefore, you can surely confirm the adsorption of the EtBr and know the tolerance limits of EtBr absorbent.
Before
After
How to use the Zero Column
The commodity is consisted of one column and two soft PVC tubes (Fig. 1).
Column: φ30×142mm, tubes: 0.5m and 1.0m in length, or 1.5m of an uncut tube.
1. Two tubes are connected to both joints of top and bottom of the column.
2. The column is set on a holder (Fig.2-4) or without a holder (Fig. 5).
3. An EtBr waste disposal bottle is put on the box of a height of 10-15 cm (Fig.6).
In the case of no holder, putting the bottle on a box is not necessary.
4. The edge of the upper tube is thrown into the bottle.
5. Suck air in the tube from the edge of a lower tube with a syringe or pipette.
The ｗaste fluid of EtBr flows with gravity and EtBr is trapped to the adsorbent in the column.
EtBr is not detected in the flowing liquid (MDA: 0.025μg/ml).
The column can treat 3-5 liters of EtBr wastes (0.5μg/ml) .
EtBr is decomposed at 260-262℃. Therefore, processing the the adsorbent column as a combustible,
but your ogranization's rule is given to priority, if any.
Zero Column Kit
Various holders
No-holder
Setting
Fig. 1
Fig. 2
Fig. 3
Fig. 4
Fig. 5
Fig. 6
Contact: Nobuaki FUJIWARA, Dr., ZeroColorSystem Laboratory, E-mail: zerocolor@osaka.zaq.jp
