doi:10.1038/nindia.2014.1 Published online 7 January 2014
A new sensor promises to detect extremely low concentrations of organophosphorous pesticides in environmental samples1 . Researchers have made the sensor using surfactant-modified gold atomic clusters.
Continuous exposure to organophosphorous compounds, used as pesticides, can cause headaches, dizziness, blurred vision, nausea, reduced heart rate, fever, coma and even death. Existing techniques for detecting such pesticides are time consuming and expensive. Some of them use enzymes that are unstable.
Previous studies have shown that clusters of gold atoms are better catalysts than bulk gold or gold nanoparticles. This is because the high surface-to-volume ratio of gold atomic clusters results in a large number of binding sites, which are accessible for catalysis and sensing.
To design a simple, fast and sensitive detection technique, the researchers fabricated the sensor by depositing gold atomic clusters on a gold electrode and stabilizing it using a surfactant compound. They then probed the efficacy of the sensor in detecting methyl parathion, an organophosphorous pesticide, at various concentrations.
Compared with bulk-gold and gold-nanoparticle-modified electrodes, the electrode containing gold atomic clusters exhibited enhanced activity for the reduction of methyl parathion. The atomic-cluster electrode gave a reduction current that was 480 and 150 times higher than those obtained using bulk-gold and gold-nanoparticle-modified electrodes, respectively.
The sensor showed excellent sensitivity and reproducibility for methyl parathion detection in environmental samples.