Sensitive Gas Analysis System on a Microchip and Application for On-Site Monitoring of NH3 in a Clean Room

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• 作者：Shinichiro Hiki ; Kazuma Mawatari ; Arata Aota ; Maki Saito ; Takehiko Kitamori
• 刊名：Analytical Chemistry
• 出版年：2011
• 出版时间：June 15, 2011
• 年：2011
• 卷：83
• 期：12
• 页码：5017-5022
• 全文大小：842K
• 年卷期：v.83,no.12(June 15, 2011)
• ISSN：1520-6882

文摘

A portable, highly sensitive, and continuous ammonia gas monitoring system was developed with a microfluidic chip. The system consists of a main unit, a gas pumping unit, and a computer which serves as an operation console. The size of the system is 45 cm width 脳 30 cm depth 脳 30 cm height, and the portable system was realized. A highly efficient and stable extraction method was developed by utilizing an annular gas/liquid laminar flow. In addition, a stable gas/liquid separation method with a PTFE membrane was developed by arranging a fluidic network in three dimensions to achieve almost zero dead volume at the gas/liquid extraction part. The extraction rate was almost 100% with a liquid flow rate of 3.5 渭L/min and a gas flow rate of 100 mL/min (contact time of 15 ms), and the concentration factor was 200 times by calculating the NH₃ concentration (w/w unit) in the gas and liquid phases. Stable phase separation and detection was sustained for more than 3 weeks in an automated operation, which was sufficient for the monitoring application. The lower limit of detection calculated based on a signal-to-noise ratio of 3 was 84 ppt, which showed good detectability for NH₃ analysis. We believe that our system is a very powerful tool for gas analysis due to the advantages of portable size, high sensitivity, and continuous monitoring, and it is particularly useful in the semiconductor field.