Gas detection equipment, which possesses characteristics of high-sensitivity and fast detection speed, is urgently needed in many fields, such as public security, police officers’ technological investigation, environmental monitoring.
Due to its small size, fast detection and sensitive response, the instrument based on Surface acoustic wave and gas chromatography (SAW GC) is widely used in the detection of explosives, water pollution and poisonous gases, proven to be a convenient and efficient detection method for environmental protection and public safety.
In the past, China was heavily import-dependent on such instruments. Professor HE Shitang and his team from the Institute of Acoustics (IOA) of the Chinese Academy of Sciences have done a lot of research work in designing and manufacturing the instrument SAW GC independently.
The paper entitled “Surface Acoustic Wave Gas Chromatography and its Application” was published in Journal of Applied Acoustics.
A SAW GC is an organic gas analyzer formed by coupling a SAW sensor with a gas chromatography. After the gas chromatography separates organic mixture into pure components, the SAW sensor would conduct quantitative detection.
The homemade instrument is designed with characteristics including high sensitivity, high speed of temperature rising in the chromatography Column (about 20°C per second), and small size. During field analysis for trace gases, it is feasible to detect broad-spectrum gas from volatile to semi-volatile organic compounds, fast in 5 minutes with high sensitivity. Hence, the instrument can be widely used in public security, environmental monitoring, food and drug testing.
A SAW GC was used in the on-spot rapid detection of the Songhua River water pollution in 2005.
Researchers analyzed the response mechanism of the SAW GC, calculated the limit of quality inspection, and designed the SAW detector, core part of the instrument. According to analysis results of the SAW sensitivity in different areas of the detector surface, researchers optimized the detector as well as docking parameters between the detector and the separation system.
Based on the design of multiple subsystems of injection enrichment and chromatographic separation, surface acoustic wave detection, numerical control and auxiliary systems, researchers developed the instrument SAW GC prototype with detection limit lowered by half, which doubles the instrument performance, than similar foreign instruments.
Apart from analysis of explosives, drugs, human odor, water pollution, the research team led by HE Shitang also investigated detection function of traditional Chinese medicine with musk as a sample, which is expected to provide technical support for the quality control of traditional Chinese medicine.
In the follow-up study, the research team will focus on methodological analysis to make SAW GC more accurately and achieve better performance. Moreover, it is hopeful to develop other targeted rapid inspection products by applying SAW GC to relative fields.
HE Shitang, LIU Jiuling, LIU Minghua, SHAO Jianying. Surface Acoustic Wave Gas Chromatography and Its Application. Journal of Applied Acoustics (Vol. 37, No.1, January 2018, Pages 1-7). DOI: 10.11684/j.issn.1000-310X.2018.01.001.
Institute of Acoustics, Chinese Academy of Sciences, 100190 Beijing, China