Stable isotope approaches are increasingly applied to better understand the cycling of inorganic nitrogen (N_i) forms, key limiting nutrients in terrestrial and aquatic ecosystems. A systematic comparison of the accuracy and precision of the most commonly used methods to analyze δ¹⁵N in NO₃⁻ and NH₄⁺ and interlaboratory comparison tests to evaluate the comparability of isotope results between laboratories are, however, still lacking.

中文翻译：

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测量无机氮形式氮同位素特征的挑战：三种常见测量方法的实验室间比较

稳定同位素方法越来越多地应用于更好地了解无机氮 ( _Ni ) 形式的循环，这是陆地和水生生态系统中限制营养物质的关键。然而，仍然缺乏对分析NO ₃ ^-和 NH ₄ ^{+中 δ 15} N的最常用方法的准确度和精密度的系统比较以及用于评估实验室之间同位素结果可比性的实验室间比较测试。