Detection of odorants in town gas by portable GC using semiconductor gas sensor

摘要

A semiconductor gas sensor is extremely sensitive to the odorants contained in town gas, such as THT (tetrahydrothiophene), DMS (dimethyl sulfide), TBM (tertiary-butyl mercaptan) and cyclohexene. We developed a new type of gas chromatograph (GC) called the XG-100 that uses a semiconductor gas sensor to measure these odorants. The GC is designed to use in identifying whether the gas detected by a detector is the result of leakage from underground pipelines that supply town gas or is naturally occurring gas. The GC can selectively detect very low concentrations of the odorants. For example, it can detect THT at a level of 10 ppb without sample enrichment. The GC uses ambient air as the carrier gas so there is no need for highly pressured cylinder gas of N2, He or H2, which are indispensable for normal GC systems. The GC weighs only 10 kg, is small in size (240×190×330 mm (W×H×D)), and can be used as a portable GC.