Research Highlight

Sniffing heavy metals

Biplab Das

doi:10.1038/nindia.2008.310 Published online 23 October 2008

An Indian research team has devised a tiny sensor made of sucrose and ultra-microelectrode (UME) for the detection of heavy metals like mercury, silver, lead, and cadmium1.

These heavy metals, if present in high levels in wastewater, may pose a threat to human health. This sensor will play a vital role in detecting the levels of heavy metals before they cross permissible limits.

To make the sensor, the researchers devised a working UME with a diameter of .000025 metre. Then the UME was modified with enzymes invertase and glucose oxidase entrapped in agarose-guar gum. Spectrophotometric and electrochemical studies showed the linear relationship between concentration of heavy metal ions and degree of inhibition of invertase. The biosensor can be reused for nine cycles.

The toxicity sequence for invertase was observed with cadmium having highest toxicity and mercury the lowest.

The authors of this work from: Department of Chemistry, University of Pune,, Maharashtra, India and Physical and Materials Chemistry Division, National Chemical Laboratory, Pune, India.


  1. Bagal-Kestwal, D. et al. Invertase inhibition based electrochemical sensor for the detection of heavy metal ions in aqueous system: Application of ultra-microelectrode to enhance sucrose biosensor's sensitivity. Biosens. Bioelectron. 24, 657-664 (2008) | Article |