Direct and rapid quantitative monitoring of ferrous ion to ferric ion levels constitute important environmental and biomedical objectives, since effective monitoring is crucial for elucidating a wide variety of cell functions, including oxygen metabolism, electron-transfer processes, and the formation of RNA and DNA.

Direct detection of corrosion rates is another important challenge. Even though many methods are popular to control the corrosion, a effective, nonexpensive sensor which can detect the corrosion at very low concentration of Ferric ion is highly essential.

In this connection, molecular recognition is a vast and rapidly emerging area that offers a novel and powerful route to molecular-based nanoscale systems that might have various applications.

In particular, optical detection and quantification of parts-per-million (ppm) levels of various chemicals, gases, and biologically relevant metal ions have recently gained much scientific interest, since their greatest advantage is that the organic sensing devices do not need to be directly wired with large-scale electronics.

Recently, Dr. Tarakeshwar Gupta, an Indian scientist working at Chemistry Dept. of   Weizmann Institute of Science, Israel has developed a sensor which can detect presence of ferric chloride even at ppm level! He reported the direct optical detection and quantification of ppm levels of ferric ions in organic and aqueous solutions

 The straightforward detection system is based on a nondestructive surface-to-solution one-electron transfer process. This redox process changes the formal oxidation state of the sensor’s monolayer.

The system can be reset with water within less than a minute, making the sensor reusable for longer duration. Also the sensor is highly selective in nature. Sensing of Fe3+ and concurrent generation of Fe2+ can be also observed with the naked eye by observing the colour change.

These sensors are very useful for industries, laboratories and mobile analyzing kits because of their small size and easy detection. With slight modification, Dr Gupta has developed the same sensor for detecting oxides of nitrogen at ppm levels in the environmental factors, since it can cause various environmental problems such as smog and acid rain.

Dr. Gupta, who is awarded with Marie Curie fellowship, is an expert in sensor developing carried out this work in association with Prof. Milko E. van der Boom, Department of Organic Chemistry at Weizmann Institute of Science, Israel. They have published this reserach work in Journal of American Chemical Society of September 2007 edition.