A Gas Sensor With Fe 2 O 3 Nanospheres Based on Trimethylamine Detection for the Rapid Assessment of Spoilage Degree in Fish.

A spherical iron oxide precursor was prepared using a solvothermal method, and then treated thermally at 400 degrees C to obtain alpha-Fe(2)O(3)nanoparticles. The structures and morphology of the as-obtained products were characterized using X-ray diffraction (XRD), transmission electron microscopy (TEM), and scanning electron microscopy (SEM). The results showed that the diameter of the alpha-Fe(2)O(3)nanoparticles was approximately 500 nm. In addition, we formed the alpha-Fe(2)O(3)nanoparticles into a thick film as a gas sensor and performed a gas sensing test. When the working temperature was set at 250 degrees C, the alpha-Fe(2)O(3)nanoparticle displayed very good selectivity and high sensitivity for trimethylamine (TMA). The minimum detection was as low as 1 ppm, and the response value for 100 ppm TMA gas was 27.8. Taken together, our findings illustrated that the alpha-Fe(2)O(3)nanoparticles could be used as a gas-sensitive material to test the freshness of fish.