Desenvolvimento de sensor portátil para monitoramento de ozônio gasoso utilizando µPADs, impressão 3D e smartphones

Abstract

Ozone is a gas considerate as an atmospheric pollutant and also shows a high value of oxidation potential and characteristic odor. Because of its high oxidation potential (Eº = 2.07 V) he has been used on many proceedings such as swimming pool cleaning, environment purification, aesthetic and teeth treatments. It is an extremely reactive molecule, easily combined with various airborne substances, and is responsible for initiating various oxidation reactions and photolytic processes. A long period of exposure to the Ozone can be extremely toxic for humans, which leads to several of breathing problems and even cancer. Within this context, the monitoring of air quality and the development of analytical methods to determine the concentration of gaseous ozone is an extreme important. So based on that, this eventual written task come up with a purpose of devolping a portable and low cost sensor to monitor the concentration of gaseous ozone using colorimetric reactions involving paper and passive sampling in a estimated period of 6 hours. It was proposed the use of smartphones, scanner, paper microfluidic devices (µPADs) and resources of a 3D printer to build a platform that allows the elaboration of the sensor. The chemical method for determination is based on the ozonolysis reaction between O3 and trissulfonate indigo dye (PTI) which results in a decrease in the blue color of the reagent. It has been utilized 20 µL of PTI in an µPAD whose diameter is 20 mm. The µPAD digital image was obtained and the color information was extracted using the RGB model. In this optimized conditions, was gathered a linear relation on the 10 mmol L -1 to 5x10-3mmol L-1 indigo concentration zone. The sensing platform was applied in the monitoring of tropospheric ozone in the region of the Institute of Chemistry of the Federal University of Uberlândia in November of 2019.