Development of a “Turn-off” fluorescent sensor for acetone from rice straw-derived carbon dots immobilized onto textile cotton mask

Chronic breath can be cited as a warning indication of diabetes-related health problems. Diabetic ketoacidosis can cause a person's breath to smell strongly like acetone, which indicates a high quantity of ketones in blood. So, it has been significant to develop a simple fluorescent textile mask to detect acetone vapor in breath of diabetic patients. On the other hand, rice straw has long been a well-known worldwide solid pollutant. As a result, developing a straightforward process to transform rice straw into a useful product is critical. Herein, a simple and pollution-free approach was devised to reprocess rice straw toward the preparation and immobilization of luminous nitrogen-doped carbon dots (NCDs) onto textile cotton mask for detection of acetone. One-pot hydrothermal carbonization of cellulose diacetate with NH₄OH as a passivating agent was used to prepare NCDs. The impregnation method was used to place a thin coating of luminous cellulose carbon dots onto cotton fabric. With an emission wavelength of 439 nm and an excitation wavelength of 381 nm, NCDs showed a quantum yield (QY) of up to 24.03 %. Acetone gas was clearly able to quench NCDs' fluorescence resulting from the inner filter effect, demonstrating excellent sensitivity and selectivity. A readout limit of 10 ppb was achieved in an acetone aqueous solution at room temperature, and a linear relationship was found for acetone concentrations of 10–200 ppb.