Hot Sauce Heat Measured with Nanotubes

[slkinsey]

Chemists measure chilli sauce hotness with nanotubes

The well-established Scoville method – currently the industry standard – involves diluting a sample until five trained taste testers cannot detect any heat from the chilli. The number of dilutions is called the Scoville rating; the relatively mild Jalapeño ranges from around 2,500-8,000, whereas the hottest chilli in the world, the 'Naga Jolokia', has a rating of 1,000,000. High performance liquid chromatography (HPLC) can also be used but this requires bulky, expensive equipment and detailed analysis of the capsaicinoids.

In Compton’s method, the capsaicinoids are adsorbed onto multi-walled carbon nanotube (MWCNT) electrodes. The team measures the current change as the capsaicinoids are oxidised by an electrochemical reaction, and this reading can be translated into Scoville units. The technique is called adsorptive stripping voltammetry (ASV), and is a relatively simple electrochemical method.

Edited May 15, 2008 by slkinsey (log)

[Chris Hennes]

Well, I'm not sure what any of that means, but it would be wonderful if by "cheap" they meant sensors that were affordable by mere individuals. I'd love to be able to check how hot a batch of chiles is before adding them to a salsa, etc. The current method results in the loss of all too many tastebuds...

[Smithy]

That looks like a slick setup. I wonder how much and how often cleaning would be needed to keep the sensor calibrated properly? Would the nanotube electrodes plug up with oxidized capsaicin?

[dougal]

However, it seems that nanotubes just might not be quite as benign as people had supposed...

Today on the BBC http://news.bbc.co.uk/1/hi/sci/tech/7408705.stm

(And there's a nanotube primer on that page for the bemused... )