化学需氧量(COD)是表征水体中有机物污染程度的一个综合性指标。 基于光电检测技术发展起来的红外透射法和紫外吸光度法相较于传统湿化学法有着精度高, 速度快, 非接触, 无二次污染等优点。 以邻苯二甲酸氢钾配置的标准液为实验对象, 分别采用近红外透射法和紫外吸光法采集标准液的近红外光谱和紫光吸光度光谱, 对光谱进行不同的预处理后运用偏最小二乘法建立红外透射光谱和紫外吸光光谱下的COD定量分析模型。 对实验结果进行数据分析后结果显示两种方法均可用于测量COD, 紫外吸光法比红外透射法有更高的相关度, 但是预测精度却不如后者。

Chemical oxygen demand (COD) is a synthetical indicator which represents the degree of organic pollution in water. The near-infrared (NIR) transmission and the UV absorbance method based on photoelectric detection technology and spectroscopy analysis have some advantages such as high precision, speed, non-contact, no secondary pollution etc compared to conventional wet chemical method. The NIR transmission spectra and UV absorbance spectra of standard solution configured with phthalate hydrogen potassium were collected respectively by MPA FTIR spectrometer (Bruker Optics Inc.) made in Germany and AvaSpec-2048-2 UV spectrometer (Avantes Inc.) made in Netherlands. After different pretreatment to the spectra, COD quantitative analysis model was established using partial least squares regression (PLS) and linear regression. The statistical analysis of COD quantitative model was implemented, and the result showed that UV absorbance method had a higher relevance but lower forecast accuracy and precision than NIR transmission method.