A bacterial method for the nitrogen isotopic analysis of nitrate in seawater and freshwater
A bacterial method for the nitrogen isotopic analysis of nitrate in seawater and freshwater
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DOI：
10.1021/ac010088e
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发表时间：
2001-09-01
影响因子：
7.4
通讯作者：
Böhlke, JK
中科院分区：
文献类型：
--
作者：
Sigman, DM;Casciotti, KL;Böhlke, JK
报道了一种在自然丰度水平上测定海水和淡水中硝酸盐(NO3-)同位素组成的新方法。该方法是基于对缺乏N2O-还原酶活性的反硝化细菌从硝酸盐生成的N2O进行的同位素分析。通过这种方式可以获得硝酸盐中氮和氧的同位素组成。在这两个配套手稿中的第一个，我们描述了氮同位素的基本方案和结果。当硝酸盐浓度降至1微米时，方法的精密度优于千分之0.2(1SD)，并准确地再现了不同标准和样品之间的氮同位素差异。对于硝酸盐含量在1微米或更高的样品，该方法的空白小于信号大小的10%，各种方法可以进一步减少它。
We report a new method for measurement of the isotopic composition of nitrate (NO3-) at the natural-abundance level in both seawater and freshwater. The method is based on the isotopic analysis of nitrous oxide (N2O) generated from nitrate by denitrifying bacteria that lack N2O-reductase activity. The isotopic composition of both nitrogen and oxygen from nitrate are accessible in this way. In this first of two companion manuscripts, we describe the basic protocol and results for the nitrogen isotopes. The precision of the method is better than 0.2 parts per thousand (1 SD) at concentrations of nitrate down to 1 muM, and the nitrogen isotopic differences among various standards and samples are accurately reproduced. For samples with 1 muM nitrate or more, the blank of the method is less than 10% of the signal size, and various approaches may reduce it further.