生化需氧量，简称 BOD，指的是微生物分解水中有机物所消耗的氧气，是反映水体污染程度的一个重要指标。目前 BOD 检测方法主要有五日检测法和微生物电极法。五日检测法耗时长，重复性差；微生物电极法虽然检测迅速，但是存在着信号漂移问题。为了满足快速准确检测 BOD 的需求，研究人员发展出了光电复合检测 BOD 的方法。该方法将全内反射椭偏光学成像系统和电化学工作站相结合，利用聚苯胺修饰电极，实现了光信号和电信号的同步输出，解决了单一信号输出时存在的信号漂移问题。
光电复合检测虽然实现了快速准确检测 BOD 的要求，但是存在着以下两个问题：一、聚苯胺检测膜层的光学响应机理以及光信号和电信号的输出关系不清；二、光电复合检测使用的反应池是单通道反应池，无法发挥全内反射椭偏光学成像系统的高通量检测优势。
为解决以上问题，一方面我们从聚苯胺检测膜层着手，在全内反射椭偏成像系统中根据聚苯胺膜层氧化还原过程中光学厚度的变化推算出光信号和聚苯胺检测膜层氧化态占比的关系，并利用能斯特方程获得电信号和聚苯胺检测膜层氧化态占比的关系，二者结合得到光信号和电信号的关系，并对其光学响应机理进行解析。另一方面，我们设计了双通道和四通道反应池，并利用所设计的反应池完成了 BOD 的高通量检测，使光电复合检测的速度获得大幅提升。
 

Biochemical oxygen demand (BOD) is an important indicator for characterizing water pollution. It refers to the oxygen consumed by microorganisms to decomposing organic matter in water. The methods for estimating BOD include five-day BOD test and BOD biosensor based on an oxygen electrode. The five-day BOD test needs a long time and has poor repeatability; the BOD biosensor based on an oxygen electrode detects rapidly, but it has the problem of signal drift. In order to realize the needs of estimating BOD fast and accurately, an optic and electrochemical combination method has been developed. This method combines total internal reflection imaging (TIRIE) ellipsometry with electrochemistry to obtain the optic and electrochemical signals simultaneously by using polyaniline modified electrodes.

For the current combination system, there are still two problems: (1) The optical response mechanism of the polyaniline film is not clear, and the relationship between the optical signal and the electrical signal is also unclear; (2) The combination system uses a single-channel reaction cell, which cannot take advantage of the high-throughput detection of TIRIE system.

In order to solve the above problems, on the one hand, we deduce the relationship between the optical signal and the proportion of the oxidized state of the polyaniline film of TIRIE system based on the change of the optical thickness during the redox process of the polyaniline film, and use the Nernst equation to obtain the relationship between the electrochemical signal and the proportion of the oxidized state of the polyaniline film. The relationship between the optical signal and the electrochemical signal is obtained, and the optical response mechanism is analyzed. On the other hand, we designed a dual-channel and four-channel reaction cell, and completed the high-throughput detection of BOD by using the designed reaction cell, which greatly improved the speed of the combination system.