Determination of formaldehyde using a novel Pt-doped nano-sized sensitive material: Operating conditions optimization by response surface method.

High working temperature is the main obstacle in the design of chemiluminescence gas sensor. In this paper, a novel formaldehyde gas sensor based on chemiluminescence on nano-Pt/Mo4V6Ti10O47 at lower temperature than 200 °C was reported. Formaldehyde can be oxidized on the catalyst and emit chemiluminescence of specific wavelength. The relative standard deviation (RSD) of the chemiluminescence intensities within 600 h by continually introducing 20 mg/m3 formaldehyde is less than 3%. There is a good linear relationship between the chemiluminescence intensity and the concentration of formaldehyde in the range of 0.007-77.0 mg/m3. The limit of detection (3σ) is 0.002 mg/m3. The experimental operating conditions optimized by response surface method are analytical wavelength of 488.07 nm, working temperature of 138.13 °C and carrier gas velocity of 164.15 mL/min, respectively. The sensitivity of the method can be increased by 4.7% under the optimized working conditions, which is especially important for determination of trace substances. The optimization method is universal for most of multi parameter processes. The sensing properties and chemiluminescence mechanism of formaldehyde on nano-Pt/Mo4V6Ti10O47 were investigated.