特征荧光光谱法定量检测水质的研究

讨论了一种可同时检测自然水体中有机物和叶绿素a含量的快速分析方法。以武汉东湖水为样品，采用激光诱导荧光(LIF)的方法测量了水体的总荧光光谱(TLS)；并用特征光谱荧光标记(SFS)技术对水体中溶解的有机物(DOM)及叶绿素a (Chl-a)的荧光光谱特征进行了分析和指认。并利用水的拉曼散射信号强度进行归一化的方法，分别得到较低浓度腐殖酸和叶绿素a的特征光谱归一化荧光强度以及它们在水体中浓度的标定曲线和线性关系式。另外， 对于较高浓度的腐殖酸溶液，确定了其特征光谱的荧光强度与浓度之间满足的函数关系。结果表明，在一定的浓度范围内，特征光谱的荧光强度与浓度之间仍然有很好的线性关系。该方法在自然水体质量的检测方面有广泛的应用前景，它能快速识别水体中的污染物，定量测量它们在水体中的含量，实现对自然水体的质量状况进行大范围的实时动态监测。

Investigation of Quantitative Detection of Water Quality Using Spectral Fluorescence Signature

A method of spectral analysis, which can simultaneously detect dissolved organic matter (DOM) and chlorophyll a (Chl-a) in natural water, was developed in the present paper with the intention of monitoring water quality fast and quantitatively.Firstly, the total luminescence spectra (TLS) of water sample from East Lake in Wuhan city were measured by the use of laser (532 nm) induced fluorescence (LIF).There were obvious peaks of relative intensity at the wavelength value of 580, 651 and 687 nm in the TLS of the sample, which correspond respectively to spectra of DOM, and the Raman scattering of water and Chl-a in the water.Then the spectral fluorescence signature (SFS) technique was adopted to analyze and distinguish spectral characteristics of DOM and Chl-a in natural water.The calibration curves and function expressions, which indicate the relation between the normalized fluorescence intensities of DOM and Chl-a in water and their concentrations, were obtained respectively under the condition of low concentration(<40 mg·L-1)by using normalization of Raman scattering spectrum of water.The curves have a high linearity.When the concentration of the solution with humic acid is large (>40 mg·L-1), the Raman scattering signal is totally absorbed by the molecules of humic acid being on the ground state, so the normalization technique can not be adopted.However the function expression between the concentration of the solution with humic acid and its relative fluorescence peak intensity can be acquired directly with the aid of experiment of fluorescence spectrum.It is concluded that although the expression is non-linearity as a whole, there is a excellent linear relation between the fluorescence intensity and concentration of DOM when the concentration is less than 200 mg·L-1.The method of measurement based on spectral fluorescence signature technique and the calibration curves gained will have prospects of broad application.It can recognize fast what pollutants are and detect quantitatively their contents in water.It is realizable to monitor the quality of natural water with real time, dynamics and inlarge area.