Colorimetric detection of gaseous acetone based on a reaction between acetone and 4-nitrophenylhydrazine in porous glass

Higher concentrations of acetone are typically detected in the air exhaled by patients suffering from diabetes; therefore, the breath acetone concentration could be expected to act as a non-invasive biomarker for diabetes. Here, an analytical chip was developed for the detection of gaseous acetone. This chip was composed of porous glass impregnated with 4-nitrophenylhydrazine (4-NPH). After exposure to an acetone atmosphere, the chip exhibited specific absorption peaks at 256 and 390 nm that were attributed to the 4-NPH acetone derivative (Acetone-4-NPH). Additionally, it was found that the absorbances at 256 and 390 nm increased upon increasing both the acetone concentration and the exposure time. The chip worked cumulatively and could detect gaseous acetone using the absorbance at either 256 or 390 nm, in addition to the exposure time. It was also found that the chip turned yellow after exposure to an acetone atmosphere. Colorimetric analysis using the RGB values obtained from photographic images of the chip showed a negative correlation between the absorbance at 390 nm and the B/G value. This allowed us to estimate gaseous acetone concentrations using color variations in the analytical chip.