Research Highlight

Mercury in red

doi:10.1038/nindia.2009.247 Published online 17 July 2009

Researchers have designed a new sensor that can detect mercury in aqueous solution as also a bug that thrives in soil1.

Aquatic microbes convert water-soluble mercury ions to methyl mercury, which bioaccumulates through the food chain posing a threat to human health and environment. The best way to detect mercury is to monitor the extent of mercury present in microorganisms such as bacteria.

The researchers synthesised a fluorescent chemical probe by reacting Rhodamine derivative (an organic compound known as L1) and 5-(dimethylamino) naphthalene-1-sulfonyl chloride (dansyl chloride). When exposed to mercury ions in the presence of near ultraviolet radiation, the new chemical sensor known as L2 underwent a chemical phenomenon known as resonance energy transfer.

When a solution of mercury ion or copper ion was added to a solution of L2, a distinct color change was noticed. The researchers also successfully studied mercury in Pseudomonas putida, a bacterium that thrives in soil.

The colourless sensor molecule turned red on binding with mercury ions. "The molecule allows visual detection of mercury," says lead researcher Amitava Das from the Central Salt and Marine Chemicals Research Institute (CSIR), Gujarat.


  1. Suresh, M. et al. Resonance Energy Transfer Approach and a New Ratiometric Probe for Hg2+ in Aqueous Media and Living Organism. Org. Lett. 11, 2740-2743 (2009) | Article |