Cetrimonium bromide (CAS 57-09-0): storage and disposal

The hazard that decides where CTAB goes is serious eye damage, which makes it a stock to keep low down in a closed container with the lid screwed fully home, never loose in a weighing area. It is a cationic surfactant, so it forms a precipitate with anionic detergents such as sodium dodecyl sulfate. In a molecular biology store keep CTAB on a different shelf from SDS and from detergent-based extraction buffers, because a leak between the two makes a sticky solid that is hard to describe. Keep it dry. Label bottles of the powder with the opening date, and note when any made-up solution on the shelf was prepared by someone else.

Normal CTAB is a white to cream powder, fine and slightly waxy, that flows when a bottle is tilted. What a technician sees first on an old jar is caking. The powder draws moisture and sets into soft lumps or a hard cake that sticks to the bottle wall, and a yellowed colour or a damp surface follows. Dust on the thread and shelf is common because the fine powder escapes every time the cap is opened. Check the label for staining and the cap for cracks. A cake that cannot be broken without force should not be forced, and a jar that has leaked onto the shelf should be recorded and left alone.

By specialist collection only. It never goes down the drain or into general waste. It is normally packed in a non-regulated or low hazard laboratory pack with compatible chemicals.

Record the jar as labelled, say whether it is the pure powder and give an approximate weight. With serious eye damage, organ effects and aquatic hazards on record, it is packed as a hazardous solid into a lab pack with compatible organic solids and collected by a registered carrier. The code in a university lab is 16 05 06*, with 16 05 08* where it is a discarded organic chemical outside a pack and 18 01 06* in a human healthcare setting. Keep it clear of the general waste, a sink or a drain, and do not rinse the jar out first because the aquatic classification is the reason.

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.