A novel method based on cataluminescence (CTL) generated on the surface of a nanometer composite oxide was proposed for direct determination of formaldehyde in air. The CTL intensity and selectivity for the determination of formaldehyde on nano-MoO₃-V₂O₅-TiO₂ at an atomic ratio of Mo∶V∶Ti of 2∶3∶5 are bigger and better than those on other nanosized composite oxides. The optimum experimental conditions were tested for nano-Mo₄V₆Ti₁₀O₄₇. Selective determination could be achieved at a wavelength of 535 nm. The surface temperature of the nanometer materials was about 265 ℃. The flow rate of air carrier was around 150 mL/min. The limit of detection of this method was 0.04 mg/m³. The linear range of CTL intensity versus concentration of formaldehyde was 0.07～34 mg/m³, and the correlation coefficient was 0.9994. The recovery of 6 testing standard formaldehyde samples by this method was 98.2%～101.4%. Common coexistence matters, such as benzene, ammonia, sulfur dioxide and ethanol, did not disturb the determination of formaldehyde, except acetone. This method allows rapid determination of formaldehyde in air.

Key words: formaldehyde, cataluminescence, nanometer composite oxide