Development of a paper-based approach for the detection of carbonyl compounds in indoor air samples

This study contributes to the development of a method to measure the level of airborne carbonyl compounds. Carbonyl compounds (CC) are very common indoor air pollutants which are widely used in building and home furnishing industries. Most CC off-gas or vaporize even at normal room temperatures, which results in an increase in the indoor volatile organic carbon levels. Acute and chronic exposure to formaldehyde can result in respiratory symptoms and eye, nose, and throat irritation in humans. Because of these adverse health effects and the increased levels of CC in indoor air and residential areas, there has been a considerable attention toward the development of sensitive methods to monitor indoor CC levels. Most methods available for monitoring indoor CC levels are indirect and time consuming. This paper describes a novel, portable, on site, low-cost and green method for regular monitoring of CC in air. 

In this method, the derivatization reagent, 2,4-dinitrophenylhydrazine (2,4-DNPH) was used to capture the airborne CC. Formaldehyde was used as the CC for this study. A novel paper-based platform soaked with 2,4 DNPH was used for the quantification of air born CC. Derivatives of CC were formed on a paper-based platform which were then directly analyzed using FTIR or an image scanner. The FTIR response for the carbonyl derivatives, which correlates with the levels of airborne CC, was used to quantify the levels of airborne CC. The same was scanned using a high resolution image scanner to obtain the RGB values and the yellow color intensity was calculated. Based on the RGB values, the produced yellow color intensity and the levels of CC produced a linear relationship. The use of an image scanner to quantify the levels of CC makes this method a portable, sensitive and on-site CC detection method. This newly developed paperbased FTIR method is agreeable with the stranded HPLC method at 95% confidence limit.