Rapid, Wide-Range, and Low-Cost Determination of Formaldehyde Based on Porous Silica Gel Plate by Digital Image Colorimetry

Abstract

A porous silica gel plate impregnated with a colorimetric reagent, 4-amino-3-penten-2one (Fluoral-P) has been fabricated for the first time to determinate formaldehyde. The reaction of formaldehyde and Fluoral-P produced a yellow product 3,5-diacetyl-1,4-dihydrolutidine (DDL), which was further photographed by a smartphone. A good linear relationship has been found between the intensity of blue component from the digital image and formaldehyde concentration in the range of 0-50 mg L −1 with low detection limit of 2.2 ± 0.1 mg L −1 . A good precision in the range of 0.59-7.75%RSD and an accuracy with the relative error of +3.7% from control samples are also obtained. These results demonstrate that our developed low-cost sensor, together with digital image colorimetry, has potential for sensitively and quickly measuring formaldehyde.