An On-Line Monitoring System for Nitrate in Seawater Based on UV Spectrum
LI Dan1, FENG Wei-wei2*, CHEN Ling-xin2, ZHANG Jun1*
1. Institute of Opto-Electronic Information Science & Technology,Yantai University,Yantai 264005,China 2. Yantai Institute of Coastal Zone Research,Chinese Academy of Sciences,Coastal Environment Engineering Technology Research Center of Shandong Province,Yantai 264003,China
Abstract:Nitrate is one of the evaluation indicators of water quality, which is particularly important for water quality monitoring. A real-time on-line monitoring system of nitrate in water is introduced in this paper. And the ultraviolet absorption technology (190~370 nm) with partial least squares method is used to detect nitrate concentration. The automated online system based on ultraviolet absorption spectrum is capable of analyzing samples without any sample preservation and without contamination problems. This system is fast, reliable, and sensitive enough for continuous use on monitoring stations and nitrate concentration can also be determined directly via its ultraviolet absorption spectrum. This system uses flow sample cell with 1cm optical path length, and a reference light is used to eliminate system error. The correlation coefficient for a linear function of the nitrate concentrations is 0.999 98. So the results of the system model test are in good correlation with the laboratory ones. Data collected has been analyzed statistically to determine how system model behave throughout the test, with special attention being paid to error analysis. As the average relative error is 0.65%, this system has greater stability and higher accuracy. The results of nitrate measurements by the field seawater tests in Yantai coast are obtained, which nitrate concentrations are about 0.2 mg·L-1 in seawater, and the recoveries of samples for standard recovery tests are in 95%~110%, it shows that this system is accurate, reliability and practicability and could be developed for detected nitrate concentration in natural water.
Key words:Nitrate;Ultraviolet spectroscopy absorption technology;Partial least squares method;On-line Monitoring
李 丹1,冯巍巍2*,陈令新2,张 骏1* . 一种基于紫外光谱法的海水硝酸盐在线监测系统 [J]. 光谱学与光谱分析, 2016, 36(02): 442-444.
LI Dan1, FENG Wei-wei2*, CHEN Ling-xin2, ZHANG Jun1* . An On-Line Monitoring System for Nitrate in Seawater Based on UV Spectrum. SPECTROSCOPY AND SPECTRAL ANALYSIS, 2016, 36(02): 442-444.
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