微量原位水质总碱度在线检测新方法研究  

Study on New Method of Online Detection of Total Alkalinity of Trace In-Situ Water Quality

作　　者：李文 程李 王利民 徐明刚 张鹏 LI Wen;CHENG Li;WANG Li-min;XU Ming-gang;ZHANG Peng(Institute of Mechanical and Electrical Engineering,North China University of Technology,Beijing 100043,China)

机构地区：[1]北方工业大学机电工程研究所,北京100043

出　　处：《光谱学与光谱分析》2021年第5期1477-1482,共6页Spectroscopy and Spectral Analysis

基　　金：国家自然科学基金项目(51205005)资助。

摘　　要：为实现原位水质总碱度快速准确检测的需求,融合顺序注射分析(sequential injection analysis,SIA)与连续光谱检测法,设计了一种小型微量原位水质总碱度在线快速检测仪,系统主要通过设计滴定池将SIA和连续光谱检测法应用于总碱度自动化滴定检测流程,并对连续光谱检测法判断滴定临界值的新方法进行实验研究。基于国标总碱度检测中工业循环冷却水及地表水总碱度的测定标准,设计了原位水质总碱度检测流程,并以顺序注射技术为控制滴定流程基础,在连续光谱扫描测量溶液检测过程的条件下,使用酚酞和甲基橙作为指示剂,对水质总碱度进行滴定分析。通过连续光谱扫描对酚酞碱度及甲基橙碱度滴定过程进行监测,以吸光度曲线552 nm处峰值归零作为酚酞碱度滴定临界值判断条件;以吸光度曲线峰值由465 nm偏移至504 nm处作为甲基橙碱度滴定临界值判断条件;分析通过滴加不同剂量酚酞和甲基橙指示剂所得溶液吸光度曲线得出最佳指示剂用量分别为0.01和0.04 mL。该系统利用最小二乘拟合算法建立总碱度测定的回归模型,并对检测系统及检测流程进行优化,实验结果表明,水质总碱度在0.20~25.00 mmol·L^(-1)范围内与盐酸消耗量线性相关,工作曲线拟合系数≥0.9942;测定总碱度重复性相对标准偏差(RSD)为0.207%~1.151%;废液量≤16 mL;最低检出限为0.03 mmol·L^(-1);样品加标回收率在97.2%~102.3%之间;与国标法对比实验结果无明显差别。利用连续光谱检测法判断滴定临界值的新方法对于提升水质总碱度检测仪的技术性能具有重要意义,可适用于系统网格化监控地表水、循环冷却水、养殖循环水等多种监测应用平台。In order to meet the needs of rapid and accurate detection of in-situ water total alkalinity,a mini online rapid tester of total alkalinity of trace in-situ water was designed by combining sequential injection analysis(SIA)and continuous spectrum detection.The system mainly applies the SIA and continuous spectrum detection method to the total alkalinity automatic titration detection process by designing the titration cell and conducting experimental research on a new method of determining the titration’s critical value by the continuous spectrum detection method.Based on the national standard of the determination on total alkalinity in industrial circulating cooling water and surface water,the detection process of in-situ water quality alkalinity was designed.Also,on the basis of the sequential injection technology as the standard of controlled titration process,under the conditions of continuous spectral scanning measurement of the solution detection process,phenolphthalein and methyl orange were used as indicators to perform a titration analysis on the total alkalinity of water quality.The phenolphthalein alkalinity and methyl orange alkalinity titration process were monitored by continuous spectral scanning.The peak value at 552 nm of the absorbance curve was used as the phenolphthalein titration threshold value.The absorbance curve’s peak value shifting from 465 to 504 nm was selected as judging conditions for the critical value of basic orange titration.The optimal indicator dosages were analyzed by the absorbance curves of the solutions obtained by adding different doses of phenolphthalein and methyl orange indicators,which were 0.01 and 0.04 mL,respectively.The system applied least-squares fitting algorithm to establish a regression model for total alkalinity determination and optimized the detection system and process.The experimental results indicate that the total alkalinity of water quality is linearly related to hydrochloric acid consumption in the range of 0.20 to 25.00 mmol·L^(-1) and the fitti

关 键 词：总碱度 微量 连续光谱 顺序注射分析 

分 类 号：TP216[自动化与计算机技术—检测技术与自动化装置]