不同水体中地表水氨氮在线监测仪准确性研究  

Study on the accuracy analysis of online ammonia monitoring instruments in different surface water

作　　者：魏文龙[1] 奚采亭 刘京[2] 贺青[1] 荆红卫[1] 马琳[1] 徐谦[1] 华蕾[1] 

机构地区：[1]北京市环境保护监测中心,北京100048 [2]中国环境监测总站,北京100048

出　　处：《环境污染与防治》2016年第12期49-53,共5页Environmental Pollution & Control

基　　金：北京市环境保护监测中心研究课题(No.JCZX20150115)

摘　　要：针对低浓度、较高浓度两种实际水体,分别选择氨气敏电极法(简称电极法)、纳氏试剂分光光度法及水杨酸-次氯酸盐分光光度法(简称水杨酸法)3种不同原理水质氨氮在线监测仪,通过标准物质核查、实际水体比对、加标回收测试及长时间连续在线监测4个方面对监测数据准确性进行比较分析。结果表明:(1)电极法在低浓度水体中监测结果准确性不足,低浓度标准物质核查合格率仅为46.20%,测试结果与真值差异显著(T检验),连续在线测试的氨氮大于0.15 mg/L(《地表水环境质量标准》(GB3838—2002)中Ⅱ类标准(0.15mg/L<氨氮≤0.5mg/L)),远高于真值(约0.03mg/L);其余两种方法表现良好。(2)水杨酸法在较高浓度水体中受到干扰,连续在线监测结果偏低,初步分析与加装前处理过滤装置有关,其准确性还需进一步研究;其余两种方法表现良好。Three pieces of online ammonia monitoring instruments with different principles were selected,including the ammonia electrode method,Nessler’s reagent spectrophotometric method,and salicylic acid spectrophotometry method.The instruments’ accuracy was tested and compared in surface water of both low-concentration and highconcentration of ammonia through verification of certified reference materials,in-laboratory comparison of actual surface water,recovery test and continuous online monitoring during long time.Two main points were found in the results.One was that accuracy was lacked in the results of the ammonia electrode method in low-concentration environment while good performance was showed by the other two methods.The results of electrode method were specifically with low test-pass-rate（46.20%）of low-concentration certified reference materials and significant differences（T test）between test results and true value of low-concentration certified reference materials.At the same time,its continuous on-line test results（more than 0.15 mg/L）were higher than true value（about 0.03 mg/L）,which could cause mis-assessment basing on the range of grade Ⅱ（above 0.15 mg/L and below 0.5 mg/L）of＂Environmental quality standards for surface water＂（GB 3838-2002）.The other was that the salicylic acid spectrophotometry method was interfered in high-concentration environment,while good performance was showed by the other two methods.What’s more,continuous on-line test results of the salicylic acid spectrophotometry method were lower than the true value and it might be caused by the pre-processing filter apparatus.

关 键 词：氨氮 在线监测 氨气敏电极法 纳氏试剂分光光度法 水杨酸-次氯酸盐分光光度法 

分 类 号：X853[环境科学与工程—环境工程]