A Simple Probe for the Colorimetric Detection of Carbon Dioxide

Abstract

The present study reports a novel approach for the chromogenic sensing of CO2 using silica nanoparticles N1 functionalized with amino and thiol moieties. The reaction of CO2 present in air with the hybrid silica nanoparticles controlled the access of a squaraine dye to the surface of nanoparticles, due to formation of carbamates between amino groups and carbon dioxide. This competitive reaction results in a simple chromogenic response to CO2. By using these bifunctionalized nanoparticles CO2 detection was achieved using suspensions of N1 in phosphate buffer or by using N1 directly in contact with air containing CO2. The use of nanoparticles that can be easily functionalized with two or more individual groups that are able to react with dyes and CO2, and the possible use of a wide range of different dyes (for signalling), makes this approach highly appealing and versatile for the design of chromo¿fluorogenic dosimeters for the evaluation of the accumulative exposure to CO2 in different environments