The invention discloses an expiration sensor, as well as a preparation method and an application thereof. The preparation method comprises the following steps: the
metal film surface of a substrate which is coated with a
metal film is coated with a
graphene oxide solution, and is dried, and the substrate with the surface coated with a
graphene oxide film is obtained; the obtained substrate is placed in hydrazine steam for reduction, and the substrate with the surface coated with a
graphene film is obtained; the graphene film surface of the obtained substrate with the surface coated with the graphene film is coated with a
metal ion solution, in-situ reduction is performed to fix a metal nanometer material on the surface of the graphene,
drying is performed, and the expiration sensor is obtained. The expiration sensor has the advantages of outstanding surface enhanced
raman scattering effect and stability, simple process in detection of
stomach cancer markers in expiratory gas, low cost and reliable results; graphene not only carries
metal nanoparticles, but also is adopted as an
absorption layer for selectively absorbing the
stomach cancer markers enriched in the expiratory gas, therefore, the expiration sensor disclosed by the invention and the application of the expiration sensor in detection of the
cancer markers in the expiratory gas has a broad prospect.