Development of a Monitoring Tape for Formaldehyde Using Hydroxylamine Sulfate and Methyl Yellow

Abstract

A porous cellulose tape impregnated with a coloring solution that includes hydroxylamine sulfate, Methyl Yellow (pH indicator; pH 2.9-4.0, red-yellow), glycerin and methanol has been developed to provide a highly sensitive means of detecting formaldehyde gas. Formaldehyde reacts with hydroxylamine sulfate to produce sulfuric acid. When a sample including formaldehyde was passed through the tape, the color of the tape changed from yellow to red. The degree of color change was proportional to the concentration of formaldehyde at a constant sampling time and flow rate. The degree of color change could be recorded by measuring the intensity of reflecting light (555 nm). No interference was observed from carbon monoxide (100 ppm), nitrogen monoxide (50 ppm), nitrogen dioxide (105 ppm), carbon dioxide (4.9%), hydrogen (100%), hydrogen sulfide (32 ppm), or hydrogen fluoride (6 ppm). The response of acetaldehyde and propionaldehyde were one fortieth and three-hundredths of that of formaldehyde, respectively. Reproducibility tests showed that the relative standard deviation of relative intensity (n=10) was 3.4% for 4 ppm formaldehyde. The detection limit was 0.1 ppm for formaldehyde at a sampling time of 5 min and a flow rate of 400 ml/min.

Electro-spinning/netting: A strategy for the fabrication of three-dimensional polymer nano-fiber/nets

“…The exploitation of highly efficient sensors for the detection of formaldehyde continues to be a significant scientific endeavor due to its possible threat to public health. Up to now, numerous formaldehyde-induced color changes of sensors that are composed of arrays of metalloporphyrins [272,273], pH indicators [274][275][276], chromotropic acid [277], and nanoporous pigments [278,279] have been successfully designed to detect formaldehyde with high selectivity. However, current colorimetric sensors for formaldehyde often use polymer film [274], cellulose tape [275,276] or even Reprinted with permission from [28].…”

Formaldehyde measurements in residential indoor air using a developed sensor element in the Kanto area of Japan

“…Multiple simultaneous measurements would not be easy, and measurements in a confined space may be impossible, because the method requires a pumping unit. Nakano has reported a formaldehyde detection method called photoelectronic spectrophotometry, which employs both hydroxylamine hydrochloride and methyl‐yellow impregnated paper (Nakano et al., 1994). Compton and Suzuki have reported a formaldehyde monitoring system based on the colorimetric reagent, 4‐amino‐4‐phenylbut‐3‐en‐2‐one (Compton and Purdy, 1980; Suzuki et al., 2003).…”

Optical chemosensors for the gas phase detection of aldehydes: mechanism, material design, and application

“…reported a disposable and porous cellulose paper impregnated with hydroxylamine sulfate ((NH 2 OH) 2 •H 2 SO 4 ), MY, glycerin, and methanol, and applied as miniature colorimetric sensor to monitor FA with yellow to red color change. 42 However, the LDL was only 100 ppb at a sampling time of 30 min, which cannot meet the detection standard of the WHO. In a follow-up study, they subsequently modified the disposable tape by adding silica gel as an adsorbent on its surface, optimizing LDL down to 80 ppb.…”

“…In the second step, the generated acid causes the color change of blending pH indicators such as Methyl yellow (MY), Methyl red (MR), Bromocresol purple (BCP), 4-nitrophenol (4-NP), and Rose anthocyanin (RA) in aqueous phase. [42][43][44][45][46] The color changes of the pH indicators arise from their structural change before and after their protonation as shown in Fig. 1.…”