PAPER-BASED TEST STRIP FOR FORMALDEHYDE GAS ANALYSIS

Abstract

A novel and one-step analysis method for formaldehyde gas using a paper-based test strip has been developed. The analysis relied on the reaction between formaldehyde and acetylacetone in the presence of ammonium acetate (Nash's reagent), which yielded a yellow-colored product of 3,5-diacetyl-1,4-dihydropyridine (DDL). The paper-based test strip has a rectangular shape, measuring 6 cm long and 1 cm wide. The test zone, which is 1 cm long and 1 cm wide, is located at one end of the strip. To prepare the test zone, the paper is dipped into Nash's reagent dissolved in sodium carboxymethyl cellulose (Na-CMC) hydrogel and then dried at 40°C. The formaldehyde test is performed by exposing the test strip to formaldehyde gas. The intensity of the yellow color is directly proportional to the amount of formaldehyde in the sample. Under optimal conditions, the developed device was able to measure formaldehyde in the two-portion linear range of 0.25–1 ppmV and 3–40 ppmV, with a value of R2 = 0.9953 and R2 = 0.9975, respectively. The limit of detection was 12 ppbV, which is lower than the air quality threshold set by the Occupational Safety and Health Administration (OSHA). From the analysis of samples including house spray paint, paint for exterior wood, and wood glue, a high recovery in the range of 90–104% was obtained. Furthermore, this paper-based test strip was found to be stable for 2 months when stored at both ambient and low temperatures. These results demonstrated that the developed paper-based test strip is promising to be used for accurately measuring formaldehyde in air samples.

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