Analytical pitfalls when using inhibitors in specific nitrification assays

IF 2 4区环境科学与生态学 Q3 CHEMISTRY, ANALYTICAL

Environmental Chemistry Pub Date : 2021-01-01 DOI:10.1071/en21118

G. Humbert, M. Sebilo, M. Chorin, V. Vaury, A. Laverman

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引用次数: 0

Abstract

Environmental context. Specific inhibitors of biological reactions in the nitrogen cycle can be used to determine the origin of reactive nitrogen species; these nitrogen species potentially degrade water quality or influence climate. However, inhibitors can potentially interfere with methods for the analysis of stable isotope ratios and concentrations of ammonium, nitrite and nitrate. The effect of this interference on several commonly used methods was investigated. These findings should help avoid the use of inappropriate analytical methods and improve data quality in studies of the nitrogen cycle. Abstract. Characterisation of the reaction steps involved in nitrification can help determine the processes that produce potentiallyharmfulenvironmentalpollutantssuchasnitrite,nitrateandnitrousoxide(N 2 O).Theuseofnitrificationinhibitors can uncouple the reactions and therefore assist in their mechanistic and isotopic characterisation. However, nitrification inhibitors can interfere with the methods for determining the concentrations and stable isotope ratios of ammonium, nitrite and nitrate. The interference of allylthiourea, hydrazine or sodium chlorate in colorimetric methods and stable isotope measurements were assessed. Ammonium concentrations were measured with the salicylate method. Nitrite and nitrate were measuredwiththeGriessreaction,withnitratefirstbeingreducedtonitritewithvanadium(III)chloride.Forthestableisotopeanalysis,nitritewasreducedtoN 2 O in a 1 :1 sodium azide and acetic acid buffer solution; preceded, when necessary, by ammonium oxidation to nitrite by hypobromite or nitrate reduction to nitrite on an activated cadmium column. Sodium chlorate did not interfere with any of the analyses and none of the inhibitors interfered with the stable isotope ratios determinationofnitrate.Allylthioureainterferedwithammoniumandnitratequantification.Bothallylthioureaandhydrazinealsoclearlyinterferedinthedeterminationofthenitrogenstableisotoperatioofammonium,whileonlyallylthioureainterferedinthedeterminationofnitrogenandoxygenstableisotoperatiosofnitrite.Althoughwesuggestmethodstoovercomesomeoftheseinterferences,ourstudydemonstratedthattheanalyticalmethodsusedincombinationwithallylthioureaorhydrazineasnitrificationinhibitorsshouldbeconsideredwithcautionwhendesigningexperiments.

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在特定硝化试验中使用抑制剂时的分析陷阱

环境背景。氮循环中生物反应的特异性抑制剂可用于确定活性氮种类的来源;这些含氮物种可能会降低水质或影响气候。然而，抑制剂可能潜在地干扰稳定同位素比率和铵、亚硝酸盐和硝酸盐浓度的分析方法。研究了这种干扰对几种常用方法的影响。这些发现有助于避免使用不适当的分析方法，提高氮循环研究的数据质量。摘要硝化反应步骤的表征可以帮助确定产生潜在有害环境污染物(如亚硝酸盐、硝酸盐和一氧化二氮)的过程。硝化抑制剂的使用可以解耦反应，因此有助于其机理和同位素表征。然而，硝化抑制剂会干扰测定铵、亚硝酸盐和硝酸盐的浓度和稳定同位素比值的方法。评价了丙烯基硫脲、肼或氯酸钠在比色法和稳定同位素测量中的干扰作用。用水杨酸盐法测定铵离子浓度。用griess反应测定亚硝酸盐和硝酸盐，其中硝酸盐首先用氯化钒还原为亚硝酸盐。为了进行稳定同位素分析，亚硝酸盐在1:1叠氮化钠和醋酸缓冲溶液中还原为ton2o;必要时，先在活化镉柱上用次溴酸盐将铵氧化为亚硝酸盐或硝酸还原为亚硝酸盐。氯酸钠没有干扰任何分析，也没有抑制剂干扰稳定同位素比率determinationofnitrate.Allylthioureainterferedwithammoniumandnitratequantification.Bothallylthioureaandhydrazinealsoclearlyinterferedinthedeterminationofthenitrogenstableisotoperatioofammonium、whileonlyallylthioureainterferedinthedeterminationofnitrogenandoxygenstableisotoperatiosofnitrite.Althoughwesuggestmethodstoovercomesomeoftheseinterferences ourstudydemonstratedthattheanalyticalmethodsusedincombinationwithallylthioureaorhydrazineasnitrificationinhibitorsshouldbeconsideredwithcautionwhendesigningexperiments。

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来源期刊

Environmental Chemistry 环境科学-分析化学

CiteScore

4.50

自引率

0.00%

发文量

审稿时长

2.7 months

期刊介绍： Environmental Chemistry publishes manuscripts addressing the chemistry of the environment (air, water, earth, and biota), including the behaviour and impacts of contaminants and other anthropogenic disturbances. The scope encompasses atmospheric chemistry, geochemistry and biogeochemistry, climate change, marine and freshwater chemistry, polar chemistry, fire chemistry, soil and sediment chemistry, and chemical aspects of ecotoxicology. Papers that take an interdisciplinary approach, while advancing our understanding of the linkages between chemistry and physical or biological processes, are particularly encouraged. While focusing on the publication of important original research and timely reviews, the journal also publishes essays and opinion pieces on issues of importance to environmental scientists, such as policy and funding. Papers should be written in a style that is accessible to those outside the field, as the readership will include - in addition to chemists - biologists, toxicologists, soil scientists, and workers from government and industrial institutions. All manuscripts are rigorously peer-reviewed and professionally copy-edited. Environmental Chemistry is published with the endorsement of the Commonwealth Scientific and Industrial Research Organisation (CSIRO) and the Australian Academy of Science.