Where is phenolphthalein found

Carbonation reduces the strength of concrete and also increases risk of corrosion of any steel supports inside a structure, with potentially catastrophic results.

Painting on a solution of phenolphthalein is an easy way to check for the extent of carbonation inside a concrete slab: pink areas are alkaline and uncarbonated while carbonated areas will remain unstained, suggesting there is a problem.

Apparently, the Hungarian government seized on the chemical as a way of solving a pressing problem when their grape harvest failed, leaving them with little choice but to import wine from other countries. These imported drinks lacked the deep red colour the people expected, so the authorities decided to add a dash of phenolphthalein to the wine supplies to redden them up. It being the early s, nobody had thought to test whether it was actually safe to use as a food additive first, which might have avoided the unpleasant result: a mass outbreak of diarrhoea.

Over in Brooklyn, New York, an enterprising Hungarian pharmacist called Max Kiss noticed this unusual story from his motherland and realised that although phenolphthalein was a terrible addition to wine it might be a useful solution to the problem of constipation.

He got to work on a concoction combining phenolphthalein with chocolate, resulting in a product he called Bo-Bos. Transferring this idea of a political blockade to a biological one, Kiss renamed his excellent laxatives Ex-Lax, and the rest is history. Ex-Lax was launched in and quickly bought out by Swiss pharmaceutical giant Novartis. Over the next 90 years it became the best-selling laxative of all time, not to mention the source of many a student prank.

Because Ex-Lax is so old, it was on the market long before stringent testing for drug safety became widespread. As far back as the s doctors were raising concerns that it could cause serious side effects including rashes, fainting and bloody stools.

But when the US Food and Drug Administration, or FDA, finally began safety tests on common over-the-counter drugs in the s, Ex-Lax was deemed to be safe for short-term treatment of constipation — a big relief for the manufacturers as well as the consumers. At the same time, another federal agency — the National Cancer Institute — was doing its own research, investigating whether common chemicals could cause cancer in animals or humans.

It took until the s to show that phenolphthalein was carcinogenic in rodents, and IARC, the International Agency for Research on Cancer, has declared phenolphthalein to be a Group 2B carcinogen, meaning that it possibly causes cancer in humans. Even so, it was banned as an over-the-counter laxative in the US and many European countries in Manufacturers using phenolphthalein in laxatives switched to other drugs, including extracts from the leaves and fruits of the senna plant and the chemical bisacodyl, which has a similar molecular structure to phenolphthalein.

That was Kat Arney on phenolphthalein and the history of Ex-Lax. But what if you prefer a nice fruit juice? Manufacturers using phenolphthalein in laxatives switched to other drugs, including extracts from the leaves and fruits of the senna plant and the chemical bisacodyl, which has a similar molecular structure to phenolphthalein. Link forensic science and the Covid pandemic to your lessons on instrumental analysis, separation techniques, data interpretation and health with UN sustainable development goals 16 and A gas widely used in electrical devices with 23, times the global warming potential of carbon dioxide.

Site powered by Webvision Cloud. Skip to main content Skip to navigation. Magnificent molecules. Source: Shutterstock. Topics Acids and bases Health Medicinal chemistry. Related articles. Feature Brilliant buffers TZ Use this infographic with your 16—18 students to develop their understanding of pH and buffers. Ideas Teach justice and cooperation through chemistry TZ Link forensic science and the Covid pandemic to your lessons on instrumental analysis, separation techniques, data interpretation and health with UN sustainable development goals 16 and Load more articles.

You're not signed in. Only registered users can comment on this article. A substance below pH 7 is considered acidic; above pH 7 is considered basic. Phenolphthalein is naturally colorless but turns pink in alkaline solutions. The compound remains colorless throughout the range of acidic pH levels but begins to turn pink at a pH level of 8. In , the German chemist Adolf von Baeyer discovered phenolphthalein by fusing phenol and phthalic anhydride in the presence of sulfuric acid or zinc chloride, the manufacture process still used today.

In the chemistry laboratory, phenolphthalein is mostly used in acid-base titrations. A solution of known concentration is carefully added into one of unknown concentration.

The phenolphthalein indicator is added into the unknown concentration. When the solution turns from colorless to pink or vice versa , the titration or neutralization point has been reached, and the unknown concentration may be calculated. In the past, phenolphthalein has been used as a laxative. It was a constituent of Ex-Lax for the over-the-counter relief of constipation. However, it was banned from use in the United States in after research showed it as a possible carcinogen cancer-causing agent.

Rosann Kozlowski is currently a freelance writer and tutor. She has a Master's Degree in Chemistry from the University of Oregon and has previously worked in the pharmaceutical industry and has taught at the middle school, high school, and college levels.

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