林业科学2016，Vol.52Issue(4)：133-141,9.DOI:10.11707/j.1001-7488.20160416
基于紫外分光光度法的树干茎流氮化学特征测定方法
A Method for Measuring Nitrogen Chemical Properties of Tree Stem-Flow with UV Spectrophotometer
摘要
Abstract
Objective]In studies of nitrogen cycling of forest system,it is important to determine nitrate nitrogen,nitrite nitrogen,ammonia nitrogen and total nitrogen of tree stem-flow accurately,the aim of this paper was to develop a method to measure the contents of these chemical properties with UV spectrophotometer.[Method]Stem flow of 8 canopy tree species from Shenlongjia Mountain were selected to measure nitrate nitrogen ( F) content in the stem-flow using 4 common methods, including UV spectrophotometry,nitrate electrode,phenol disulfonic acid and thymol,and to decide which method was the best for detecting nitrate nitrogen ( F ) content; the stem-flow was oxidize at 125 ℃ for 45 minutes by using refined potassium persulfate solution and total nitrogen ( T ) was then detected using UV spectrophotometer and nitrate cathode respectively. The stemflow was oxidized with potassium permanganate solution and the total content of nitrate and nitrite ( B) was s then measured with UV spectrophotometer. The content of nitrite was calculated as B-F,and ammonia as T-B,then the content of ammonia was compared with that detected by the method of Nessler ’s reagent. [Results]The UV spectrophotometry was the best method among the 4 methods in detecting nitrate nitrogen,with an accuracy and a precision of 106. 19% ± 8. 26% and 3. 0%,respectively; the accuracy and precision of nitrate cathode,thymol and phenoldisulfonic acid were102. 5% ± 12. 08%and 2. 0%,107. 44% ± 9. 26% and 4%,43. 62% ± 26. 39%and 12%,respectively. The accuracy and precision of total nitrogen ( T) measured with UV spectrophotometry were 94. 62% ± 2. 19% and 2. 0%; In contrast,the accuracy of nitrate electrode method was 98. 93% ± 37. 64%%,indicating that it was not applicable to some tree species. Accuracy and precision of nitrate and nitrite(B) measured with UV spectrophotometry were 100. 97% ± 2. 85%and 4. 0%,indicating that it was perfect in detecting nitrate and nitrite. The precision of ammonia and nitrite calculated from T,F and B were up to 3. 0% and 4. 0% respectively,suggesting that our method was suited for detecting ammonia and nitrite. [Conclusion]Tree stemflow could be oxidized with potassium persulfate and potassium permanganate,then nitrate nitrogen ( F ) , total nitrogen ( T ) and total content of nitrite and nitrate all can be measured directly with UV spectrophotometer,and nitrite and ammonia of stemflow could be calculated with them.关键词
紫外分光光度法/亚硝酸盐氮/硝酸盐氮/氨态氮/全氮Key words
UV spectrophotometric/nitrate nitrogen/nitrite nitrogen/ammonia nitrogen/total nitrogen分类
农业科技引用本文复制引用
杨林,王传华,李涛,王力,郭义东..基于紫外分光光度法的树干茎流氮化学特征测定方法[J].林业科学,2016,52(4):133-141,9.基金项目
国家自然科学基金项目(31370536)。 （31370536）
