Murexide (CAS 3051-09-0): storage and disposal

In a school prep room murexide normally sits with the other indicator powders, and what matters is that the shelf is dry. It belongs in a dry, labelled, well organised store, dated on arrival if the label carries no date, and kept apart from food grade supplies and from the wet reagents that tend to share a bench cupboard. A fine coloured powder marks surfaces, so a shallow tray under the jar shows a leaking cap straight away. Because stock is held in small amounts for years, keep the cap tight and avoid storing it above or beside open bottles of aqueous solutions, where damp is most likely to reach it.

Few signs are particular to this powder, so the container usually shows more than the contents. Check for clumping or caking where damp has got in, a colour that looks duller or patchier than a fresh jar, stains around the cap and on the shelf, a faded label and a missing date. Indicator dyes of this kind can lose their usefulness without looking dramatically different, so a jar that has outlived its teaching use may still look acceptable. If the label has gone or the supplier is unknown, say so on the record. Do not open a caked jar to break it up.

We arrange this by specialist collection. We do not publish a drain or general waste route for any chemical. It is normally packed in a non-regulated or low hazard laboratory pack with compatible chemicals.

It is not normally classified as hazardous, yet it stays a chemical waste and must be described accurately, which is why it still goes by specialist collection and not out with the general rubbish. It is grouped with other solid indicator dyes in a lab pack, under waste code 16 05 09. A waste transfer note covers the move. The jar must not go into a sink, a drain, general waste or a skip, and nobody should try to treat the powder first. Give the label wording, the container type and the approximate quantity when requesting collection.

Usually held as: solid.

Tell us the container size and how many you hold. An estimate is enough to start with, and some items cannot be priced until someone has looked at them.