BENGALURU: Researchers from the Department of Organic Chemistry at the IISc have developed a paper-based sensor for detecting tiny volumes of hydrogen peroxide, a chemical used widely in household and healthcare products like hand sanitiser as a disinfectant, in rocket fuel as a propellant, in biological cells, and also as a starting material in peroxide-based explosives.
The low-cost and biodegradable paper sensor could be extensively used in detection of peroxide-based explosives, especially as mixing concentrated hydrogen peroxide and acetone with an acid catalyst is known to form sensitive explosives triacetone triperoxide (TATP) and diacetone diperoxide (DADP). Detecting hydrogen peroxide efficiently is crucial as peroxide-based explosives can be traced using hydrogen peroxide, which is sometimes used as a starting material. Experts explained that although pure hydrogen peroxide solutions are not usually explosive at atmospheric pressure, higher concentrations become explosive in a temperature range just below the boiling point of a liquid medium it is packed in.
The technique used by the IISc researchers involves preparing a gel from a solution containing a specially designed molecule, treated with a liquid that has hydrogen peroxide, and air-drying them on a thin paper disc about 0.45 cm in diameter. The paper disc emits green light when placed under a ultra-violet lamp, only in the presence of hydrogen peroxide.
The intensity of the light was found to be directly proportional to the concentration of hydrogen peroxide, an IISc release said. “You can actually visualise this green emission with the naked eye... All you need is a simple UV light source,” explains Arnab Dutta, PhD student in the Department of Organic Chemistry and first author of the study titled ‘Naked-eye detection of hydrogen peroxide on photoluminescent paper discs’, published in the journal ACS Sensors.
Because the paper disc is low-cost, biodegradable and easy to use, it could serve as a powerful tool in low-resource settings, even for testing biological fluids like blood.