Micro gas analytical system by means of radial electrophoresis pump

本研究开发了一种简单的、可在现场使用的液体流动法，并将其应用于大气污染物的监测。首先，设计并研究了一种新的流动方式--径向电泳泵。在这种方法中，气体吸收液只用几伏特的电压就可以电泳式流动。在测试开始时，它看起来是有效的，但实际上液体是由水的电分解产生的气泡移动的。然后，对其他方法进行了试验，吸收液可以流经玻璃芯片中10厘米长的微通道和几十伏的等长硅胶管。其次，还测试了重力法和压缩法，它们的效果都很好，特别是在使用小型压缩机和压力传感器进行压缩时。将这些流动分析方法应用于多种气体分析。一种是在微毛细管芯片上制作的液滴环电极，与传统计时电流法相比，该装置具有很快的响应速度。将压缩法应用于由管状气体扩散洗涤器和固态光电器件组成的高灵敏度H_2S测定系统中。该方法可以连续测量极低水平的H_2S，甚至可以测量背景水平的H_2S，因为可以获得稳定的无脉动液流。该系统可以由电池供电，在没有交流电源的情况下，可以在野外使用数天。结果表明，该系统与传统的带式测定仪有很好的相关性，而且具有更好的时间分辨率和浓度分辨率。

In this research, a simple liquid flow method, which could be used in the field, was developed and it was applied to monitoring of atmospheric pollutants. First, a new concept of flowing method "radial electrophoresis pump" was designed and investigated. In this method, gas absorbing solution is flowed electrophoretically with only several volts of voltage. In the beginning of the test it seemed that it worked, but actually the liquid was moved by bubbles generated by the electrodecomposition of water. Then, other methods were tested ; the absorbing solution could be flowed through 10-cm micro channel in a glass chip and same length silicone tubing with several tens of volts. Next, gravity method and compressing method were also tested and they worked well especially compressing with a small compressor and pressure sensor. These flow methods were applied to some kinds of gas analysis. One is a droplet ring electrode fabricated on a chip of micro capillary This device showed very fast response compared to the conventional chronoamperometry The compressing method was applied to a high sensitive H_2S determination system that was composed of tubular gas diffusion scrubber and solid state photo devices. Very low level of H_2S even back ground level could be measured continuously in this method, because stable liquid flow without pulsation was obtained. This system could be operated by battery and could be used for several days in outside field without AC power source. The results obtained with the system showed a good correlation with a conventional tape meter, and further, the time and concentration resolutions were much better in this system.