温度和光源带宽引起的氨氮在线监测仪系统误差研究  

Research on System Errors of On-line Ammonia Nitrogen Monitor Caused by Temperature and Bandwidth of Light Source

作　　者：张红艳 张欢 洪陵成[1,2] 王翔 

机构地区：[1]江苏德林环保技术有限公司南京211105 [2]河海大学环境科学与工程学院南京210000

出　　处：《现代科学仪器》2016年第1期136-140,共5页Modern Scientific Instruments

摘　　要：水环境中氨氮的实时在线监测具有重要意义，而现有分光光度法水质氨氮在线监测仪易受环境温度影响造成测量误差。本文通过研究温度对监测仪核心部件——光电检测系统影响发现，环境温度可以引起发光二极管（LED）光源强度和光电池光电压变化，引起氨氮在线监测仪器吸光光度系统的误差可迭-1．3％。而LED光源的带宽对吸光光度法系统的造成的测量误差随待测物浓度的增大而增大。当氨氮浓度为0．485mg／L时，温度变化20℃，引起LED光源光谱和光电池开路电压变化导致的对硝基苯酚法氨氮吸光度误差为-1．47％，浓度测量值的误差为～2．56％。这种温度造成的系统误差在其他光度法在线监测仪器中普遍存在，建议提高LED光源单色性并对光电池进行温度控制或软件程序补偿，减小这种系统误差。The real-time on-line monitoring of ammonia nitrogen in water environment is of great significance, while the existing spectrophotometric method for ammonia nitrogen on-line monitor is easy to be influenced by the environment temperature which caused the measurement error. In this paper, the effect of temperature on the core components of the monitoring instrument--the photoelectric detection system is studied. And the intensity of light-emitting diode （LED） light source and light voltage of photocell could be influenced by environment temperature, which caused the error of the on-line monitoring system of ammonia nitrogen up to be -1.3%., while the measurement error caused by the LED light source is increasing with the increase of the concentration of the analyte. When the concentration of ammonia nitrogen was 0.485mg/L and the change of temperature was 20℃, the absorbance error of P-nitrophenol method caused by the change of LED light source spectrum and open circuit voltage of photocell is -1.47%, while the error of the concentration measurement was -2.36%. This system error caused by the temperature is common in other on-line ammonia nitrogen monitor using photometric method. It is suggested to improve the monochromaticity of LED light source and temperature control or software program compensation for photocell to decrease the system error.

关 键 词：LED光谱带宽 硅光电池 环境温度 氨氮在线监测仪 系统误差 

分 类 号：O661.1[理学—分析化学]