Acridine orange (CAS 494-38-2): storage and disposal
Green against DNA and orange against RNA under a fluorescence microscope, acridine orange is a stain held as powder in university, pathology and histology stores. It is classified as capable of causing genetic defects, and it is light sensitive. Those two facts shape everything: the jar is kept locked and kept dark, and an old jar that has sat in the light has a different story from one that has not.
- CAS number
- 494-38-2
- Form
- Solid
- Storage class
- Toxic
- Signal word
- Danger
- Usual EWC code
- 16 05 06*
Serious health hazard
What to do this week
- Check the label is readable and write down the opened date if it is not already there.
- Check it is stored as toxic stock and apart from the items listed under "Do not store with".
- If you no longer need it, add it to your disposal list so it goes on the next collection.
Safe storage in a school or lab
Keep it in controlled storage, segregated according to its safety data sheet and chemical compatibility requirements. The classification, that it may cause genetic defects, calls for a locked cabinet with a stock record. Light sensitivity means the jar belongs in the dark, in its original opaque or amber container or inside a closed box within the cabinet. Never leave it on an open bench or windowsill. Keep the closure secure and the label dated. If the cap thread is contaminated, leave the deposit undisturbed and report its condition. Because it is a fluorescent stain, keep it away from UV sources as well as daylight.
How to tell it has deteriorated
Look at the container and label first: an orange stain at the cap, a smear on the label or powder on the shelf shows the seal has failed or the jar was handled carelessly. Because the dye is light sensitive, a jar that has stood in a lit place, particularly a clear one, may have changed colour or faded, and that change is a reason to treat the contents as unreliable. Powder that is caked, damp or hardened has absorbed moisture. Few other signs can be relied on. A faded label, an unreadable date or a missing stock record leaves an unknown jar, to be left sealed and listed.
How it must be disposed of
By specialist collection only. It never goes down the drain or into general waste. It is normally packed in a toxic laboratory pack with compatible chemicals.
Nothing about this dye is to be emptied into a sink, a drain or the general bin, and no one should try to make it safe or clean the jar first. Because it may cause genetic defects, say clearly if powder has spilled on the outside of the container and bag it separately. The request should give the form, jar size and whether it has been kept in the dark. A university or laboratory store uses 16 05 06*, and a human healthcare pathology service uses 18 01 06*. Keep it in its dark container, sealed and upright, until it is collected.
| EWC code, laboratory chemicals | 16 05 06* |
|---|---|
| Discarded organic chemical, not a laboratory pack | 16 05 08* |
| Human healthcare setting | 18 01 06* |
| Hazardous waste | Yes |
The code depends on where the waste came from and what it is mixed with. Use the waste code finder to see why.
Do not store with
- OxidiserToxic and oxidising stock are stored apart. A reaction could release toxic vapours.
- AcidToxic stock is stored apart from acids. Several toxic salts release toxic gas in contact with acid.
Named chemicals to keep apart
- Acetic acidToxic stock is stored apart from acids. Several toxic salts release toxic gas in contact with acid.
- Calcium hypochloriteToxic and oxidising stock are stored apart. A reaction could release toxic vapours.
- Hydrochloric acidToxic stock is stored apart from acids. Several toxic salts release toxic gas in contact with acid.
- Hydrogen peroxideToxic and oxidising stock are stored apart. A reaction could release toxic vapours.
- Nitric acidToxic stock is stored apart from acids. Several toxic salts release toxic gas in contact with acid.
- Potassium nitrateToxic and oxidising stock are stored apart. A reaction could release toxic vapours.
- Potassium permanganateToxic and oxidising stock are stored apart. A reaction could release toxic vapours.
- Sulfuric acidToxic stock is stored apart from acids. Several toxic salts release toxic gas in contact with acid.
Common quantities we collect
Usually held as: solid.
Part-used bottles and full containers are both fine. Tell us the size and how many, and an estimate is enough for a first price.
Where it is commonly held
Hazard statements
- H340 May cause genetic defects.
Precautionary statements
- P203 Obtain, read and follow all safety instructions before use.
- P280 Wear protective gloves, protective clothing, eye protection and face protection.
- P318 If exposed or concerned, get medical advice.
- P405 Store locked up.
- P501 Dispose of contents and container in accordance with local, regional, national and international regulations.
Substance as classified, dilutions may differ.
Questions
Why must acridine orange be kept in the dark?
It is light sensitive, so keep it in its original opaque or amber container, inside a closed box in a locked cabinet, away from daylight and UV sources.
Does the classification differ from other DNA stains?
Acridine orange is classified as capable of causing genetic defects, a stronger wording than the suspected effect given for some other DNA stains, so it needs particularly careful handling.
What if the powder has changed colour?
Light can alter a light-sensitive dye, so a colour change means the contents are unreliable. Do not test it. Record the change and list the jar for collection.
Which code applies to a university research store?
University and other laboratory stores use 16 05 06*, whereas human healthcare pathology services use 18 01 06*. Name the setting on the request so the entry follows the place the stock was held.
