RESUMO
A gas-sensor utilizing cataluminescence (CTL) on nanosized gamma-Al2O3 + Nd2O3 for measuring low concentrations of gaseous ethylene dichloride (EDC) was developed. The results showed that gamma-Al2O3 nanoparticles as a catalyst offered high sensitivity and selectivity in the detection of EDC. The addition of a small quantity of Nd2O3 increased the intensity of CTL more than two-fold. Quantitative analysis was performed at a wavelength of 400 nm and at an optimal temperature of 279 degrees C, and the optimal flow rate of carrier gas was 320 mL/min. Under the optimized conditions, the linear range of CTL intensity vs. concentration is 6-5000 ppm (R = 0.9996; n = 7), with a detection limit of 2 ppm. The response time is <5 s. No interference or only very low levels of significant interference were observed when substances such as formaldehyde, n-hexane, methyl benzene, carbon tetrachloride, chloroform and benzene were passed through the sensor.
