Identification and determination of formaldehyde, benzene and ammonia in air based on cross sensitivity of cataluminescence on single catalyst

Abstract

A cataluminescence (CTL) based method for simultaneously identifying and determining formaldehyde (HCHO), benzene (C6H6) and ammonia (NH3) in air was proposed. CTL is emitted from the surface of nano-sized Ti2YAl3O10 contained in a CTL reactor. Three analysis wavelengths of 350nm, 440nm and 560nm were selected. The surface temperature of sensing materials was 340°C. The flow rate of air carrier was 140mL/min. The limits of detection were 0.07mg/m3 for HCHO, 0.10mg/m3 for C6H6 and 0.15mg/m3 for NH3. The linear ranges of CTL intensity versus analyte concentration were 0.2–66.4mg/m3 for HCHO, 0.5–71.5mg/m3 for C6H6 and 0.5–63.8mg/m3 for NH3. The recoveries of 10 testing standard samples was 97.5%–103.1% for HCHO and 96.8%–102.8% for C6H6 and 98.1%–103.7% for NH3. Common coexistence matters, such as acetaldehyde, toluene, ethyl benzene, methylamine, ethylamine, methanol, ethanol, sulfur dioxide, hydrogen sulfide and carbon dioxide, did not disturb the determination. The relative deviation of CTL intensities was less than 3% for continuous 200h detection, which demonstrated the longevity and steady performance of nano- Ti2YAl3O10 to HCHO, C6H6 and NH3.