A sensor originally developed for monitoring pH in oil wells is being adapted for the pharmaceutical, food and beverage and chemical manufacturing industries. The technology, which was invented by Richard Compton at Oxford University's Physical and Theoretical Chemistry Laboratory, is being further developed and commercialised by San Francisco company Phathom Nanosensors. Oxford's technology transfer company Isis Innovation has licensed the technology to Phathom. The technique replaces traditional glass electrode pH sensors with one that uses an electrode made of modified carbon nanotubes on a graphite surface.rn'Our technology has several key advantages over the glass electrode technology still widely used in industry,' said Compton. He claimed his sensor is more accurate, which enables tighter control of pH-critical manufacturing processes.rnUnlike glass electrodes, the sensors are also self-calibrating. Jamie Ferguson, project manager at Isis, explained that the sensor works using 'working, reference and counter' electrodes. The working electrode is made of modified carbon nanotubes deposited on a graphite surface. 'The advantage of nanotubes is they give you a huge surface area,' he said. The reference electrode, an organic compound called anthraquinone, responds to the changes in the pH level. The counter electrode is polyvinylferrocene, a material that does not change its redox chemistry when the pH changes.
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