基于连续光谱法联合测定NH_(3)-N、COD方法研究  

Research on Testing NH_(3)-N and COD in Water Quality Based on Continuous Spectroscopy Method

作　　者：李文 陈银银 罗学科[1] 何娜 LI Wen;CHEN Yin-yin;LUO Xue-ke;HE Na(Institute of Mechanical and Electrical Engineering,North China University of Technology,Beijing 100144,China)

机构地区：[1]北方工业大学机电工程研究所,北京100144

出　　处：《光谱学与光谱分析》2023年第1期254-259,共6页Spectroscopy and Spectral Analysis

基　　金：国家自然科学基金项目(51205005);北京市科技创新服务能力建设项目(PXM2017-014212-000013)资助。

摘　　要：针对地表水中Ⅰ—Ⅴ类水域、地下水、工业废水对氨氮及化学需氧量准确快速联合测定的需求,融合光谱分析法中的连续光谱法与顺序注射技术(SIA),基于地表水国家检测标准,以氨态氮(NH_(3)-N)、化学需氧量(COD)原位水质参数为检测对象,设计了一种小型微量原位水质NH_(3)-N、COD高效快速检测仪。该系统主要依据自主设计的基于紫外灯照射消解与加热密闭消解方法同时进行的消解池结构以及基于光谱扫描设计的的检测池结构,达到快速消解稳定检测的目的。同时系统基于分光光度法优化了检测流程,测定开始COD消解的同时,待检测池中的NH_(3)-N指数显色后的配位化合物进行光谱扫描测定,消解后,进行COD的测定,整个检测过程相比国标检测法缩短至少60 min,可以实现25min内自动完成NH_(3)-N及COD的测定,大大节约时间成本。绘制经光谱扫描显色反应后配位化合物的吸光度与连续波长曲线可得:NH_(3)-N、COD分别于690和445 nm处具有明显吸收峰,经读取峰的吸光度值,采用最小二乘法分别建立NH_(3)-N、COD回归建模,拟合回归方程并计算相关系数,绘制相应参数的吸光度-浓度工作曲线。实验结果表明:在0~2 mg·L^(-1)浓度范围内,NH_(3)-N标准工作曲线相关系数r≥0.9987,且浓度与吸光度成正相关。重复性相对标准偏差为1.36%~1.68%,加标回收率为97%~102%;在0~50 mg·L^(-1)浓度范围内,COD标准工作曲线相关系数r≥0.9978,浓度与吸光度呈负相关。重复性相对标准偏差为2.14%~2.48%,加标回收率为97.6%~102.95%。系统的测定结果准确、直线性与稳定性良好,具有较高的可行性与可靠性。基于SIA与连续光谱法联合测定NH_(3)-N、COD的方法研究,为拓宽光谱法在水质快速检测领域的应用、提高检测效率等方面的研究具有重大价值。Aiming at the requirements for accurate and rapid combined determination of ammonia nitrogen and chemical oxygen demand in surface waters of classⅠ—Ⅴ,groundwater and industrial wastewater,this paper combines continuous spectrometry and Sequential Injection Analysis(SIA)in spectral Analysis,based on the national standard for surface water detection,taking in-situ water quality parameters of ammonia nitrogen(NH 3-N)and chemical oxygen demand(COD)as the detection objects,designing a micro,efficient and rapid detection instrument for NH 3-N and COD in-situ water.The system mainly relies on the self-designed digestion cell structure based on ultraviolet lamp digestion with heated closed digestion,and the detection cell structure based on the spectral scanning design to achieve the purpose of rapid digestion and stable detection.It also optimized the detection process based on spectrophotometry.At the beginning of COD digestion,the coordination compounds in the detection tank after NH 3-N index coloritization were determined by spectral scanning.After digestion,COD was determined,the whole detection process was shortened by at least 60 minutes compared with the national standard detection method.It can automatically complete the determination of NH 3-N and COD within 25 minute,greatly saving time cost.Plotting the absorbance and continuous wavelength curve of coordination compounds after spectral scanning color reaction:NH 3-N and COD have obvious absorption peaks at 690 and 445 nm,respectively.After reading the absorbance value at the peak,the least square method is used to establish regression modeling for NH 3-N and COD,fitting the regression equation and calculating the correlation coefficient,and drawing the absorbance-concentration working curve of the corresponding parameters.The experimental results show that the correlation coefficient r of the NH 3-N standard working curve is≥0.9987 in the concentration range of 0~2 mg·L^(-1),and the concentration is positively correlated with the absorbance.The rela

关 键 词：氨态氮 化学需氧量 连续光谱法 顺序注射技术 

分 类 号：TP216[自动化与计算机技术—检测技术与自动化装置]