Development and fabrication of a paper based analytical device using iron oxide nanoparticles to detect arsenic in aqueous samples

Ground water arsenic contamination is one of the major global issues in recent days. The long exposure of arsenic can cause hazardous health effects like skin cancer, lung cancer as well as heart diseases. Conventional methods for monitoring arsenic level is often strenuous and require highly skilled personals to perform the measurements, thus there is a need to develop a simple and cost- effective techniques for quick and continuous monitoring. Paper-based approach for detecting the arsenic is a low-cost, non-instrumental method and provides on-site detection of water contaminants. In this study a rapid, simple and affordable method for arsenic detection was developed. This methodology involves the generation of arsine gas inside the analysis system that reacts with the silver nitrate present on the paper analytical device (PAD). This reaction between silver nitrate and arsine gives a colored product that was detected by scanning the colored intensity with image processing software. The iron oxide nanoparticles act as a reducing agent that causes the generation of arsine gas from arsenic. These nanoparticles were synthesized through green technology by using henna extract. The whole reaction takes place in the glass vial with the rubber cap on it at which the PAD was placed. Experimental parameters like concentration of reducing agent, silver nitrate and reaction time were evaluated that affects the performance of the analytical process. Under optimal conditions the method showed the detection limit of 0.005ppm.