CeNS develops portable sensor to detect heavy metal ions in water

Centre for Nano and Soft Matter Sciences (CeNS) has developed a compact solid-state sensor that can detect the heavy metal ions in water. It was developed by a team of researchers led by Dr. Pralay K. Santra at the Centre for Nano and Soft Matter Sciences. 

Need for the sensor:
Heavy metal ions like mercury, lead, and cadmium show severe potential threats to living beings. These metal ions can easily be accumulated in the human body. It cannot be detoxified by any chemical or biological processes. The health hazards associated with heavy metal ions in water demands the development of efficient and portable sensors for rapid onsite detection of these ions. This need led to the development of visual sensors, which can effectively detect heavy metal ions rapidly (within seconds) under ambient conditions.

Compact solid-state sensor:
♦ Compact solid-state sensor is a portable device as the quantum dots can be excited with handheld UV light of 254 nm. It can help onsite detection in remote areas. 
♦ The sensor can detect the heavy metal ions, for example, lead ions (Pb2+) down to 0.4 parts per billion (ppb) for efficient onsite detection.
♦ The sensor film was prepared by forming a composite between manganese doped zinc sulfide quantum dots and reduced graphene oxide on a glass substrate.
♦ These particular quantum dots are water-soluble and have high photoluminescence (~30 %) quantum yield, making them suitable for luminescence-based sensing. 
♦ If a drop of water containing heavy metal ions such as mercury, lead, cadmium, etc. are added to the composite film, the emission of the film will be quenched within seconds.
♦ The team is currently developing strategies to improve the selectivity of the detection.