以邻苯二甲酸氢钾配制的化学需氧量标准液为实验对象, 采集1～800 mg·L-1标准液的紫外吸收光谱, 运用偏最小二乘法(PLS)建立了不同谱区的校正模型, 结果表明, 265～310 nm谱区模型的相关性最高, 误差最小; 为了消除硝酸盐与温度对化学需氧量测量的影响, 分别研究了不同浓度的硝酸钠与不同温度条件下标准液的紫外吸收光谱的变化情况, 结果表明硝酸钠在208～238 nm有明显的吸收, 265～310 nm谱区模型不受硝酸钠吸收的影响, 温度的升高会导致标准液的紫外光谱吸光度的增大, 通过预测分析建立了不同校正模型下的温度补偿函数。

Configured standard solution of chemical oxygen demand with potassium hydrogen phthalate was used as experimental subjects, collected ultraviolet absorption spectra of the standard solution in the range of 1～800 mg·L-1, were collected, and PLS (partial least squares) algorithm was used to establish the correction model of different spectral region,the results showed that. The model in the spectral region of 265～310 nm had the highest correlation and smallest error; In order to eliminate the impact of nitrates and temperature on the detection of the COD , studied the changes of the UV absorption spectrum with different concentrations of sodium standard solution and different temperature. The results showed that absorption of nitrate in 208～238 nm was apparent, and the model for spectral region of 265～310 nm was free from the influence of nitrate; In the full range of spectrum, temperature rising leads to an increase in absorbance, thus the temperature compensation model was established for the different spectral region through predictive analysis.