钠氏试剂分光光度法测定水中氨氮有关问题探讨  

Discussion on problems about determination of ammonia nitrogen in water by Nessler's reagent spectrophotometry

作　　者：马占青[1] 俞卫阳[1] 干亚平[1] 

机构地区：[1]杭州职业技术学院临江学院,浙江杭州310018

出　　处：《人民长江》2017年第14期19-22,共4页Yangtze River

基　　金：2014年度杭州市精品课程"家居环境与健康"(杭教高师[2014]51号)

摘　　要：钠氏试剂分光光度法测定氨氮具有操作简便、灵敏度高等特点,因而成为目前水环境监测中普遍使用的方法。对《水质氨氮的测定纳氏试剂分光光度法》(HJ 535-2009)中有关校准曲线标准工作溶液的量取、校准曲线实验点分布、比色皿的选择和样品溶液的稀释等问题进行了探讨。结果表明:在氨氮校准曲线制作时,氨氮标准工作溶液的量取选用5.00 m L的分度吸量管完成全部取样,操作次数和工作量适中并满足HJ 535-2009标准的精度要求;校准曲线上的实验点分布或取舍不应随意变更,否则会影响测量精确度;选用20 mm比色皿时测定误差较小。若待测样品的浓度较高时,其稀释宜选用5.00 m L以上的单标线吸量管;若考核样品浓度为0~100μg/m L时,综合各种边界条件可以有0,5,25,50倍和0,2,10,50倍2个合理的溶液稀释方案,可分别选用5.00,10.00,50.00 m L和5.00,25.00,50.00 m L的单标线吸量管取样稀释。Nessler′s reagent spectrophotometry has the advantages of simple operation and high sensitivity in nitrogen measurement,so it has become a common method in water environmental monitoring. Studies were conducted on standard working solution measurement and experimental point distribution of calibration curve, cuvettes seclection and sample solution dilution in Water quality-Determination of ammonia nitrogen-Nessler′s reagent spectrophotometry （HJ 535-2009）. The results show that： the measurement of standard nitrogen-ammonia solution is proper to select 5.00 mL graduated pipette to complete the total samples when drawing calibration curve, which can make operation times and workload appropriate and meet the requirements of HJ 535-2009 standard accuracy; the experimental point distribution on calibration curve or the option should not be arbitrary, otherwise it will affect the measurement accuracy; the 20 mm cuvette is favorable to reduce measurement error. If the concentration of measured sample is higher,it is better to choose single marking pipette more than 5.00 mL to dilute the solution; if the examination sample concentration is 0-100 μg /mL, there are 2 reasonable solution dilution schemes of 0,5,25,50 times and 0,2,10,50 times,and the two options are selecting 5.00,10.00,50 mL and 5.00,25.00,50.00 mL single marking pipette sampling dilution respectively.

关 键 词：氨氮 钠氏试剂 分光光度法 校准曲线 比色皿 

分 类 号：X171[环境科学与工程—环境科学]