水体的温度变化对测定溶解有机物浓度的影响

用激光诱导荧光(LIF)方法研究了水体的温度变化对溶解有机物(DOM)发射荧光强度的影响。随着温度的增加，DOM的荧光强度和水的拉曼散射强度不断降低。在20～75 ℃范围之内，对归一化荧光强度与温度关系曲线进行线性拟合，计算出归一化荧光强度随温度升高的变化梯度平均值为-5.24×10-4 ℃-1,根据归一化荧光强度与浓度的关系，给出了所测DOM的浓度随着温度升高的平均下降速率为-3.45×10-3 (mg·L-1)·℃-1。因此，在这一温度范围内测量时，假设归一化荧光强度不变，则温度变化将引起DOM浓度最大为8.45%的相对变化。

The Influence of Temperature Change on Determined Concentrations of Dissolved Organic Matter in Water

The influence of temperature change on the determined concentrations of dissolved organic matter (DOM) in water was investigated by laser induced fluorescence (LIF) technique in laboratory. The temperature was altered within the range of 20 to 75 degrees C, and the intensity of DOM fluorescence and water Raman scattering were found to decrease with rising temperature. A linear fit of the normalized fluorescence intensity versus temperature yielded a mean value of the temperature coefficient of -5.24 x 10(-4) x degrees C(-1), and a mean value of the temperature coefficient of -3.42 x 10(-3)(mg x L(-1)) x degrees C(-1) was obtained according to the relationship between normalized fluorescence intensity and concentration of DOM. The temperature change will cause relative changes of up to 8.45% in DOM concentration within the range of 20 to 75 degrees C if we assume that the normalized fluorescence intensity remains the same.