全自动流动注射-分光光度法测定土壤中氨氮

Determination of Ammonia Nitrogen in Soil by Automatic Flow Injection-Spectrophotometry

传统的氯化钾溶液提取分光光度法测定土壤中氨氮时,需要加入硝普钠-苯酚显色剂混匀后一定时间再加入二氯异氰尿酸钠显色剂,这个过程中人为接触苯酚等有机试剂的时间较长,对人体和环境有一定的危害;且传统的比色法显色时间至少需要5 h,显色时间较长,分析效率较低。应用全自动流动注射-分光光度法测定土壤中氨氮,考察了提取试剂的厂家、浓度等两个因素对实验的影响。采用氯化钾(1.00 mol/L)提取液配制标准曲线,在0~10.00 mg/L线性关系良好,方法检出限为0.031 mg/kg,样品相对偏差均小于5%,实际样品回收率为89.0%~114%。与传统的氯化钾溶液提取分光光度法相比,全自动流动注射-分光光度法具有自动进样、分析速率快,试剂耗量低,检测范围宽、保护环境等优点,适用于一般农用地、场地调查样品中氨氮的检测。

In the traditional potassium chloride solution extraction spectrophotometric determination of ammonia nitrogen,it is necessary to add sodium nitrocellulose-phenol chromogenic agent and mix it together for a certain time after adding sodium dichloroisocyanate chromogenic agent,in this process,artificial exposure to phenol and other organic reagents for a long time,which has a certain harm to the human body and the environment.Automatic flow injection-spectrophotometry analyzer is used to determine ammonia nitrogen in soil,the influence of different factors of the manufacturer and concentration was investigated.A standard curve of potassium chloride extract of 1.00 mol/L was prepared,the linear relationship is good in the linear range of 0—10.00 mg/L.The detection limit of the method is 0.031 mg/kg,the relative deviation of the sample is less than 5%,and the recovery rate of the actual sample is 89.0%—114%.Compared with the traditional spectrophotometric method of potassium chloride solution,automatic flow injection spectrophotometry has the advantages of automatic sample entry,fast analysis rate,low reagent consumption,wide detection range and environmental protection,etc.This method is suitable for the detection of ammonia nitrogen in general agricultural land and site survey samples.