Research on Method of Eliminating Spectral Background Signal of Water Quality Monitoring Based on Dynamic Reference

In view of the dynamic effects on spectrum measurement’s background signal of water quality monitoring caused by the absorption of turbidity, chroma and a variety of unknown materials, according to Beer-Lambert Law. the relationship between solvent and solute has been analyzed; and combining with the on-line water quality monitoring principle based on spectral analysis, the concept of "dynamic reference" has been put forward. Meanwhile, a method based on the "dynamic reference" to eliminate the background interference of spectrum measurement signal has been proposed too, Applying the above signal processing method to the self-developed water quality monitoring instrument. the field contrast experiment with the national standard analysis methods for on-line measuring the hexavalent chromium in the same actual environmental water sample has been carried out; and the accuracy of measuring results by "dynamic reference" are better than that by "static reference". Moreover, the accuracy also meets the superior to the national environmental protection standard (the relative error of contrast experiment to actual water sample A≤10%). The experiment results show that the proposed signal processing method can dynamically eliminate the background spectrum influence caused by water matrix interference, so as to ensure the accuracy of spectral measurement signals and improve the accuracy of on-line water quality monitoring instrument.