Mullins Lab Standard Operating Procedure
Chemical Waste Protocol:
Researchers use a very small amount of Ethidium Bromide to complete their gels (1%). The EtBr station is located in room 352 across from the chemical prep station.
When researchers are done with their buffer solution, (which contains the EtBr that they were using), they pour the buffer into a large jug, which is marked as EtBr buffer to be filtered, which we filter, then dispose of. Here are the steps to this process of filtration:
1. A flask is connected to the vacuum line to assist in the filtration. The flask has a filter system on top of it, which the EtBr is poured into.
2. Pour the buffer into the filter system from the jug marked as EtBr buffer to be filtered, and place lids back on all containers.
3. Turn on the vacuum system to allow buffer to filter.
4. After the buffer has completely filtered thru the system, take off the filter system, and pout the contents of the flask into the large flask marked as filtered EtBr buffer.
5. You will continue this process until the entire buffer is gone from the jug.
6. When the large flask marked as filtered EtBr buffer is full, (up to 4000 ml/4 liters), pout the contents down the sink, and you will record the amount, the date, the time, your initials, and what it was that you poured down the sink, (e.g., filtered EtBr buffer waste), on the sewer disposal log next to the sink. It will be important that the buffer type is indicated (e.g., 1x TAE). You will also record this disposal in the waste notebook.
7. After the large flask is emptied, it is a good idea to replace the filtration system with a new one that is found on the bench in back of the station, or behind the station, above the microwave, on the shelf. Basically, one filter system can filter 4000 ml of solution. You will know when it is time to replace the system when the flow of buffer into the holding flask becomes slow, very slow. You will also make check marks on the label on the filter itself, every time you empty the holding flask into the large flask.
8. Always remember to replace all lids on all containers in the EtBr station.