Micro gas analytical system by means of radial electrophoresis pump

本研究开发了一种可现场应用的简单液流法，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法“径向电泳泵”。在这种方法中，气体吸收溶液仅在几伏电压下以电流方式流动。在测试开始时，它似乎工作，但实际上液体是由水的电分解产生的气泡移动。然后，测试了其他方法;吸收溶液可以在几十伏的电压下流过玻璃芯片中的10 cm微通道和相同长度的硅胶管。接下来，重力法和压缩法也进行了测试，他们工作得很好，特别是压缩与一个小的压缩机和压力传感器。这些流动分析方法已应用于多种气体的分析。一种是在微毛细管芯片上制作的液滴环电极，与传统的计时电流法相比，该装置具有非常快的响应速度。将压缩法应用于由管式气体扩散洗涤器和固体光电器件组成的高灵敏度H_2S测定系统。该方法可连续测量极低浓度的H_2S，甚至背景浓度，因为液体流动稳定，无脉动。该系统可采用蓄电池供电，在野外无交流电源的情况下可连续使用数天。用该系统获得的结果显示出与常规带式流量计良好的相关性，并且该系统的时间和浓度分辨率更好。

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.