Biofluorometric\nAcetone Gas Sensor of Sub-ppbv Level\nSensitivity

Acetone gas in exhaled breath and skin gas is produced\nwhen fatty\nacids are used as an energy source in the body. The selective and\nsensitive continuous measurement of acetone gas would be useful for\nthe early screening of diabetes mellitus, a condition characterized\nby increased fatty acid metabolism. In particular, there is a growing\nneed for acetone gas sensors that enable the wearable measurement\nof trace concentrations of acetone gas emitted through the skin. In\nthis study, we improved the sensor’s sensitivity by optimizing\nthe fluorescence measurement system and flow cell of a previously\ndeveloped biofluorometric acetone gas sensor (bio-sniffer) using secondary\nalcohol dehydrogenase. To evaluate the performance of the improved\nacetone bio-sniffer, we constructed a dilution system to prepare acetone\ngas at subparts per billion by volume (ppbv) levels and verified its\naccuracy using gas chromatography–mass spectrometry. As a result,\nthe dilution system was able to prepare 0.1 ppbv of acetone gas with\na coefficient of variation of 5%. The improved acetone bio-sniffer\ndemonstrated quantitative characteristics in the concentration range\nof 0.5–1000 ppbv, with a lower limit of quantification that\nwas 40 times better than that of the conventional acetone bio-sniffer.\nIn the future, this system is expected to be used for continuous measurement\nof acetone gas released through the skin.