Simultaneous determination of benzene and formaldehyde in air by cross cataluminescence on nano-3TiO₂-2BiVO₄

A novel method based on cross cataluminescence (CTL) generated on the surface of nano-3TiO₂-2BiVO₄ was proposed for simultaneous determination of benzene and formaldehyde in air. Two analysis wavelengths 470 nm and 600 nm were selected for this method. The surface temperature of sensing materials was 375 °C. The flow rate of air carrier was 135 mL/min. The limits of detection of this method were 0.12 mg/m³ for benzene and 0.05 mg/m³ for formaldehyde. The linear ranges of CTL intensity versus analyte concentration were 0.25-57.5 mg/m³ for benzene and 0.10-51.3 mg/m³ for formaldehyde. The recoveries of 5 testing standard samples by this method were 96.6-103.1% for benzene and 97.2%-102.8% for formaldehyde. Common coexistence matters, such as toluene, ethyl benzene, acetaldehyde, ethanol, ammonia, sulfur dioxide and carbon dioxide, did not disturb the determination. The relative deviation (RD) of CTL signals from continuous 120 h detection of gaseous mixture containing benzene and formaldehyde was less than 2%, which demonstrated the longevity and steady performance of nano-3TiO₂-2BiVO₄ to benzene and formaldehyde.