ABSTRACT
A novel method based on cross sensitivity of cataluminescence (CTL) on nano-Ti3CeY2O11 was proposed for simultaneous determination of formaldehyde, benzene and sulfur dioxide in air.The relations between the concentrations of formaldehyde, benzene and sulfur dioxide and their CTL intensities were respectively ascertained at three wavelengths.The accurate concentrations of formaldehyde, benzene and sulfur dioxide can be calculated by superimposed total CTL intensities.The three analysis wavelengths are 420 nm, 535 nm and 680 nm.The surface temperature of the sensitive materials is 280℃.The carrier gas flow rate is 130 mL/min.The detection limits (3σ) are 0.04 mg/m3 for formaldehyde, 0.05 mg/m3 for benzene and 0.10 mg/m3 for sulfur dioxide, respectively.The linear ranges of CTL intensity versus analyte concentration are 0.08-75.60 mg/m3 for formaldehyde, 0.1-101.40 mg/m3 for benzene and 0.3 to 115.00 mg/m3 for sulfur dioxide.The recoveries of 12 testing standard samples by this method are 96.4%-103.7% for formaldehyde, 97.8%-102.5% for benzene and 97.2%-103.3% for sulfur dioxide.Common coexisting substances, such as acetaldehyde, toluene, hydrogen sulfide, ammonia, methanol, ethanol and carbon dioxide, do not disturb the determination.The relative deviation of CTL signals of continuous 200 h detection for gaseous mixture containing formaldehyde, benzene and sulfur dioxide is less than 2%, which shows the longevity of the nanometer composite oxide to formaldehyde, benzene and sulfur dioxide.This method makes full use of the cross sensitive phenomenon, and can realize the on-line analysis of formaldehyde, benzene and sulfur dioxide in air.