Phenolphthalein

Phenolphthalein has a chemical formula of C20H14O4 and is often written as 'Hln' or 'phph'. It appears as an odourless white to cream powder in its solid state. Phenolphthalein is a chemical compound which is widely used for detecting end-points in acid-based titrations. In acidic solutions it turns colourless, whilst in basic solutions it turns pink. At high levels of alkalinity, it turns bright red. Phenolphthalein is one of the most widely-used indicators and is also used as a veterinary cathartic and as a laxative. It is incompatible with strong oxidizing agents and alkalis.

When used in analysis, Phenolphthalein is usually dissolved in alcohol as it is insoluble in water. Phenolphthalein was for many years used as a laxative but has been removed from over-the-counter treatments due to concerns that it may be a carcinogen.

Another use of Phenolphthalein is as a 'disappearing ink' where hidden graphics can be read and can then fade away again, as if by magic. This is particularly effective in children's books. A well-known use of Phenolphthalein in a children's toy was evident in 'Hollywood Hair Barbie' whose white-blonde hair 'magically' developed pink stars when sprayed with a clear hair mist.

Phenolphthalein solution is available in a variety of different strengths depending on its intended purpose. For example it is available as percentage solutions such as Phenolphthalein 1%, Phenolphthalein 0.5%w/v, Phenolphthalein 0.2% w/v and Phenolphthalein 0.05%. Ask your supplier of Phenolphthalein to advise you at to the most appropriate strength for your particular application.

As when handling any chemical product care should be taken when working with or handling Phenolphthalein. Wear appropriate personal protective clothing (PPE) when handling quantities of the substance and protect skin, eyes and mucous membranes from accidental contact.

Always read the MSDS (Material Safety Data Sheet) supplied with the material before commencing work with Phenolphthalein. If you have any concerns about using Phenolphthalein consult your approved Phenolphthalein supplier who will be pleased to give advice.