Dichlorophenolindophenol (CAS 620-45-1): storage and disposal

The container or form it arrives in matters here, since the sodium salt and the solution are kept differently. The dry salt goes in a dry, labelled store, with the lid tightly closed, away from food grade supplies. A bottle of DCPIP solution should be kept out of bright light, such as a windowsill or open shelf under a lamp, and in a tray. Because the salt may cause respiratory irritation, avoid opening the jar in an unventilated cupboard. Date every bottle of solution on arrival or when it was filled, since an undated bottle cannot be judged at all.

In its working state the solution is a strong blue, and the powder is a dark, rich colour. What does not look right is a solution that has gone pale, murky or colourless on its own, which suggests it has faded with age or light and no longer behaves as an indicator. A dried crust at the neck, a split label, and a powder that has caked from damp are the container signs. A bottle with no date or maker is the commonest problem. Record the colour you see, the level and the cap condition, and do not open a cloudy bottle.

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.

Waste code 16 05 06* applies to a laboratory chemical in a lab pack, and 16 05 08* where it counts as discarded organic chemical outside one. The salt and the solution are listed as separate items, since the solution is a liquid and the salt is a solid. Both go by specialist collection, and neither should be poured down a sink, because nobody should assume a coloured indicator solution is safe to flush. Record the label wording, the container type and the approximate volume, and keep the cap tight until collection.

Usually held as: sodium salt, DCPIP solution.

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.