Love-wave gas sensors based on surface functionalized iron oxide nanoparticles has been developed in this research. Amino-terminated iron oxide nanoparticles were deposited, by a spin coating technique, onto the surface of Love-wave sensors, as a very reproducible gas-sensing layer. The gases tested were organic solvents, such as butanol, isopropanol, toluene and xylene, for a wide and low concentration range, obtaining great responses, fast response times of a few minutes (the time at which the device produced a signal change equal to 90%), good reproducibilities, and different responses for each detected solvent. The estimated limits of detection obtained have been very low for each detected compound, about 1 ppm for butanol, 12 ppm for isopropanol, 3 ppm for toluene and 0.5 ppm for xylene. Therefore, it is demonstrated that this type of acoustic wave sensor, with surface amino-functionalized nanoparticles, is a good alternative to those ones functionalized with metal nanoparticles, which result very expensive sensors to achieve worse results.
Acknowledgments
This work was supported through Programa de Apoyo a Proyectos de Investigación e Innovación Tecnológica (PAPIIT) UNAM (Mexico) projects IA103016 and by the Ministerio de Economía y Competitividad (Spain) under the projects TEC2013- 48147-C6 and TEC2016-79898-C6-1-R (AEI/FEDER, EU). This research has made use of the infrastructures of the Spanish ICTS Network MICRONANOFABS partially supported by MINECO.