An efficient, steady method based on cataluminescence (CTL) generated on the surface of a nanometer composite oxide was proposed for direct determination of ethanol in air. The gas sensor using nano-TiO₂-ZrO₂-La₂O₃ (Ti∶Zr∶La＝5∶2∶1) as a probe showed high selectivity for ethanol at a wavelength of 620 nm and satisfying activity at the surface temperature of 310 ℃. The optimum flow rate of air carrier was around 130 mL/min. The detection limit of this method was 1.3 mg/m³. The linear range of CTL intensity versus concentration of ethanol was 2～230 mg/m³, and the correlation coefficient was 0.9990. The recovery of 10 testing standard ethanol samples by this method was 97.4%～102.7%. Common coexistence matters, such as formaldehyde, acetone, benzene, ammonia, sulfur dioxide and carbon dioxide, did not disturb the determination of ethanol. The gas sensor displayed good stability for continuously introducing ethanol over 120 h.

Key words: ethanol, cataluminescence, nanometer composite oxide, sensor