海水的化学需氧量大小直接决定海水水质的污染程度, 传统的紫外-可见光波段检测时荧光干扰较大, 近红外光波段检测时, 水分子红外吸收峰影响较严重。提出一种基于拉曼光谱的海水化学需氧量检测方法, 以不同浓度的模拟海水样本为被测对象, 确定特征拉曼位移为981.6 cm-1, 对拉曼光谱预处理后, 通过偏最小二乘法对拉曼光谱的相对强度与碱性高锰酸钾法检测得到的海水化学需氧量进行回归建模。实验结果显示, 训练集和预测集相关系数达到0.99, 验证集决定系数可达到0.990 9, 预测均方根误差为0.79 mg/L。

The chemical oxygen demand (COD) of seawater directly determines the degree of pollution of seawater water quality. The fluorescence interference in the traditional ultraviolet(UV)-visible light detection is relatively large, and the infrared absorption peak of water molecules is seriously affected when the chemical oxygen demand of seawater is detected by the near infrared light. A COD detection method for seawater based on Raman spectroscopy was proposed. The simulated seawater samples of different concentrations were used as the subjects to determine the characteristic Raman displacement of 981.6 cm-1. After pre-processing of Raman spectroscopy, by partial least square method, a regression model was established for the relative strength of Raman spectrum and the seawater COD values measured by potassium permanganate method . The experimental results show that the correlation coefficient between the training set and the prediction set reaches 0.99, the determination coefficient of the verification set reaches 0.990 9, and the predicted mean square root error is 0.79 mg/L.