Real-Time Continuous Rapid Colorimetric Sensor for Gaseous Formaldehyde Determination by Increasing Gas-Liquid Reaction Rate

Formaldehyde can have detrimental health effects on humans. To reduce exposure to formaldehyde, several methods have been reported for gas-phase formaldehyde determination including chromatography, capillary electrophoresis electrochemical and so on. Among these methods, colorimetric sensor is a promising technique for its high sensitivity, selectivity, low cost and compactness. However, it usually takes tens of minutes for one measurement. In this paper, a real-time continuous rapid formaldehyde determination system based on colorimetric sensor was presented. Through the study of the relationship between inlet diameter of gas and its bubble size and reaction speed, the reaction time is reduced to 1/3 with an ability to detect formaldehyde concentrations as low as 0.02 ppm. The system can also measure the formaldehyde concentration continuously and automatically, which is vital for locating pollution sources.