doi:10.1038/nindia.2013.57 Published online 29 April 2013
Researchers have designed a new kind of sensor that can detect minute traces of para-nitrophenol (PNP), a water pollutant1. This sensor will be very useful for monitoring the extremely low levels of PNP in environmental samples.
PNP is widely used in the manufacture of drugs, fungicides and dyes and to darken leather. PNP mainly enters the environment during manufacturing and processing. Animal studies have shown that it reduces the ability of blood to transport oxygen to tissues and organs and causes irritation to the skin and eyes.
An efficient PNP-monitoring device is needed to monitor accidental spills to the environment. However, no previous studies have developed an effective sensor capable of detecting low concentrations of PNP.
The researchers produced a new PNP sensor by fabricating an electrode by electrochemically imprinting PNP with polyvinyl-sulphonic-acid-doped polyaniline deposited on an indium–tin–oxide-coated glass substrate. This yielded the desired PNP sensor.
They then carried out electrochemical studies to evaluate the efficacy of the PNP sensor in measuring PNP levels in environmental samples. In these electrochemical studies, the sensor detected extremely low levels of PNP and was stable for 45 days. It showed good precision with a relative standard deviation of 2.1% and good reproducibility with a standard deviation of 3.78%.