Diamond electrodes laced with boron and coated with iridium oxide could provide a cheap and simple way of detecting arsenic at exceptionally low concentrations, claims a group of Oxford chemists.

According to Richard Compton, professor of physical chemistry, the electrodes can detect arsenic contamination at less than 3 micrograms per litre; the World Health Organization warns against drinking water with more than 10 micrograms of arsenic per litre.

The Oxford group claims to have made its equipment robust and portable. Diamond doped with boron provides a stable conductor while the layers of iridium oxide offer corrosion protection, notes Compton. The idea, he adds, is to produce 'single shot, disposable electrodes allowing easy and cheap field measurements for arsenic'.

Carolyn Ackers