Ribena revelation inspires budding scientists

By Associate Professor Allan Blackman

This article was orignally published in the Otago Daily Times on Monday 2 April 2007.

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Chemistry has had a pleasingly high profile over the past month or so.

At the beginning of March, our department was visited by the 1987 Chemistry Nobel Laureate, Professor Jean-Marie Lehn, which was widely reported in the media. In addition, Prof Margaret Brimble, of the University of Auckland department of chemistry, was one of five academics to receive the 2007 L’Oreal-Unesco Women in Science Laureate Award, and she made a number of appearances in various media.

However, in terms of media attention, these notable scientists have been completely upstaged over the past week by Anna Devathasan and Jenny Suo, two students from Pakuranga High School, whose chemical investigations at a science fair ended up costing GlaxoSmithKline $217,500.

Science fairs are held throughout the country annually and are open to budding young scientists from primary, intermediate and secondary schools. In 2004, Anna and Jenny, like many students, entered their local science fair, choosing to look at the amounts of Vitamin C in various types of fruit juices.

The method they used to carry out this analysis is a procedure called a titration. The material of interest is placed in a flask, and to this is gradually added a solution that reacts rapidly with it.

By determining the volume of solution required for complete reaction, the amount of the material of interest can be calculated. In this case, the solution used was iodine and it was added to the various fruit juices.

A solution of iodine is very deeply coloured, but it reacts rapidly with vitamin C to give a colourless product. Therefore, it is straightforward to tell when all the vitamin C in a sample of fruit juice has reacted by noting the point at which the iodine colour first starts to persist.

In chemical terms, vitamin C is a reducing agent (also known as an antioxidant in popular parlance) and iodine is an oxidising agent — they undergo a chemical reaction because the vitamin C loses electrons which are then gained by the iodine.

Anna and Jenny originally carried out this titration on eight different juices, and found a range of vitamin C levels. However, they were surprised by the low amounts they found in Ribena — the second lowest of all the juices tested.

Their concerns led them to an appearance on Fair Go in 2004, and eventually to the Auckland District Court on March 27 where GlaxoSmithKline was fined a notinsignificant sum of money for 15 breaches of the Fair Trading Act.

Anna and Jenny’s work (they were 14 years old at the time) brings to mind that of Emily Rosa, a 9-year-old from America who, in 1996, devised a simple experiment that completely debunked “therapeutic touch”, a quack technique that supposedly allowed practitioners to detect and manipulate a human “aura” — in the process she became the youngest ever author of a paper in a peer-reviewed medical journal. It seems that one is never too young to do good science.

I’m absolutely thrilled to see that Anna and Jenny’s work has been given the worldwide coverage it deserves. In addition, I’m astonished that the quality control department at GlaxoSmithKline, with all its undoubted hi-tech instrumentation, couldn’t measure vitamin C levels as accurately as two students using high school laboratory equipment.

This whole saga serves as a lesson to all food and drink manufacturers, especially those who advertise the supposed health benefits of their products. And if I was at all involved in the production of food or drink, I would be quite worried at the moment — Anna and Jenny’s work will have inspired a whole bunch of budding scientists in this year’s forthcoming school science fairs. And who knows what they will find?