Development of a sensitive gas sensor by trapping the analytes on nanomaterials and in situ cataluminescence detection

An optical sensor for ethanol has been proposed by trapping the analytes on sensing nanomaterials at room temperature and detecting them in situ by recording the cataluminescence (CTL) signals with fast elevated temperature. Sensing nanomaterials of ZrO2 were directly deposited on heating filament which enables the temperature programming for trapping and detecting the interested analytes. The miniaturized sensing unit has low incandescent radiation so as to provide the high signal-to-noise ratio. Under the optimized conditions, the linear range for the determination of ethanol vapor is 1.0 × 10−3 to 1.0 mg L−1. A detection limit (S/N = 3) is 2.0 × 10−4 mg L−1 (0.1 ppm), which is improved about 3000-fold for ethanol compared with previous CTL sensors. The relative standard deviation (RSD) is 1.2% (n = 7) for ethanol samples at a concentration of 0.08 mg L−1. The stability was demonstrated by continuous reaction with ethanol for 120 h. This sensor has been applied to monitor the ethanol concentration in human expired gas after drinking, and the results agreed well with the reference values. This miniature ethanol sensor offers higher sensitivity, faster response and lower power consumption, which make it very promising in developing hand-hold sensing device for field detection.