Development of multiple-gas analysis method using the ball surface acoustic wave sensor

In the fields of energy exploitation, and for the safety and security of society, portable multiple-gas sensors are essential. Although the gas chromatograph (GC) is applicable to multiple-gas analysis, it is not portable. As a result, we have proposed the ball surface acoustic wave (SAW) GC using a ball SAW sensor, which realizes high sensitivity by the ultramultiple roundtrip propagation of a SAW and a separation column fabricated by micro-electro- mechanical-system technology. However, it takes too long for a portable GC such as the ball SAW GC to analyze mixed gases of high and low molecular weights at the same time. In this study, we developed the forward-flush (FF) method, involving two (or more) separation columns with a ball SAW sensor inserted after each column, to solve the above problem. Using the ball SAW GC with the FF method, we analyzed mixed gases of natural gas components and volatile organic compounds.