基于小波变换测定水质中硝酸盐含量

Determination of Nitrate in the Mixture Aqueous Solution of Nitrate and Nitrite Based on Wavelet Transform

为了测定硝酸盐与亚硝酸盐混合液中硝酸盐含量,利用硝酸盐对照液和硝酸盐与亚硝酸盐混合液的紫外吸收光谱数据进行连续小波变换,提取与硝酸盐有关的特征小波系数,实现硝酸盐含量的光谱检测。实验结果表明:用所得特征小波系数建立与浓度的线性回归方程,所取硝酸盐浓度具有良好的线性关系(r=0.9992),平均回收率为98.59%。本法与传统的方法相比,要求条件较低,不需要物理或化学的分离,分析速度快,有望应用于在线监测污水中测定硝酸盐的含量。

To determine the nitrate content in the mixture solution of nitrate and nitrite, wavelet transform is used to analyze the UV absorption spectra of the control solution of nitrate and mixture of nitrite and nitrate. The eigen wavelet coefficients correlated with the concentration of nitrate are obtained and the nitrate content can be detected. The linear regression equation established by eigen wavelet coefficients,the nitrate content is linear （r= 1. 008） and the average recovery rate is 98.59 %. Compared with traditional methods, this method is simpler and does not required physical or chemical separation with high analysis speed and accuracy. This method is expected to be applied to the online monitoring of the nitrate content of wastewater.