Colorimetric pad for low-concentration formaldehyde monitoring in indoor air
2
Issued Date
2022-07-04
Resource Type
ISSN
08574421
eISSN
2586940X
Scopus ID
2-s2.0-85115816906
Journal Title
Journal of Health Research
Volume
36
Issue
4
Start Page
781
End Page
790
Rights Holder(s)
SCOPUS
Bibliographic Citation
Journal of Health Research Vol.36 No.4 (2022) , 781-790
Suggested Citation
Wongsakoonkan W., Pengpumkiat S., Boonyayothin V., Tangtong C., Laohaudomchok W., Phanprasit W. Colorimetric pad for low-concentration formaldehyde monitoring in indoor air. Journal of Health Research Vol.36 No.4 (2022) , 781-790. 790. doi:10.1108/JHR-09-2020-0428 Retrieved from: https://repository.li.mahidol.ac.th/handle/123456789/85724
Title
Colorimetric pad for low-concentration formaldehyde monitoring in indoor air
Author's Affiliation
Other Contributor(s)
Abstract
Purpose: The purpose of this study was to develop an accurate, selective, low-cost and user-friendly colorimetric pad to detect formaldehyde at low concentration. Design/methodology/approach: 1-phenyl-1,3-butanedione, a reactive chemical, was selected to develop the colorimetric pad for indoor air formaldehyde measurement. Silica nanoparticle impregnated with the reactive chemical was coated on the cellulose filter surface to increase the reactive site. A certified formaldehyde permeation tube was used to generate six varied concentrations between 0.01 and 0.10 ppm in a test chamber. The color intensity on the pads was measured using an image processing program to produce a formaldehyde concentration reading chart. The colorimetric pad was tested for optimum reaction time, accuracy, precision, stability, selectivity and shelf life. Findings: The color of the pads changed from white to yellow and the color intensity varied with the concentrations and appeared to be stable after exposure to formaldehyde for 8 hours. At room temperature, the stability of the pad was 7 days, and shelf life was 120 days. The accuracy, precision and bias of the pad were 12.38%, 0.032 and 6.0%, respectively. Carbonyl compounds, benzene and toluene did not interfere with the reading of this developed colorimetric pad. Originality/value: The developed colorimetric pad meets NIOSH's criteria for an overall accuracy of ±25%, bias = 10%. They were accurate at low concentrations, user-friendly and had low cost compared to an electronic direct reading instrument (cost of chemicals and materials was 21.50 Bath or 0.69 USD per piece) so that favorable for the use of general people for health protection.