Water quality COD spectral measurement device and measurement method

The invention discloses a water quality COD spectral measurement device. A flow-through cell is fixed in a shading box and at least two surfaces of the flow-through cell are nonopaque; a light source is fixed in the internal surface of the shading box; a detector is fixed on the internal surface of the shading box under the light source; a first sample cell and a second sample cell are arranged outside the shading box; a first water pipe is communicated with the flow-through cell and a to-be-measured water sample; a water pipe is communicated with the flow-through cell and the first sample cell; a third water pipe is communicated with the flow-through cell and the second sample cell; a fourth water pipe is connected with a water outlet in the bottom of the flow-through cell and the external part of the shading box; a peristaltic pump is arranged on the fourth water pipe; a fifth water pipe is connected with the top of the flow-through cell and the external part of the shading box; a single-chip microcomputer is used for controlling all devices. The invention further discloses a spectral measurement method for measuring the water quality COD by adopting the water quality COD spectral measurement device. The water quality COD spectral measurement device can quickly and accurately measure the water quality COD and can perform online measurement in a circulatory and automatic manner; the absorption spectrum is closer to the actual water sample condition as compared with the spectrum used for directly measuring nitrate solution prepared from distilled water and an anion surfactant.