1.1 本试验方法适用于通过碱性过硫酸盐消解后离子色谱法（IC）分析未过滤水样中以硝酸盐形式的总氮（有机氮+氨-N+硝酸盐-N+亚硝酸盐-N）和以正磷酸盐形式的总磷。 1.2 通过计算确定总凯氏氮(TKN)。为了测定TKN，从未消化的样品中减去消化样品中的硝酸盐氮和亚硝酸盐氮（见第节 4 、试验方法总结）。 1.3 检测限(LOD)、定量限(LOQ)和报告范围 表1 基于该检测方法的两步工艺:消化和分析步骤。由于消化步骤需要样品稀释，LOD和LOQ高于未消化样品。报告范围、LOD和LOQ可以根据几个因素进行修改和改进（参见第 6 、干扰）。 1.4 显示方法检测限（MDL）以供参考。消解试剂含有背景硝酸盐，导致较高的检测限。MDL将在实验室间研究（ILS）完成后显示。 1.5 以SI单位表示的值将被视为标准值。本标准不包括其他计量单位。 1.6 本标准并不旨在解决与其使用相关的所有安全性问题（如果有）。本标准的使用者有责任在使用前建立适当的安全、健康和环境实践并确定法规限制的适用性。 1.7 本国际标准是根据世界贸易组织技术性贸易壁垒委员会发布的《关于制定国际标准、指南和建议的原则的决定》中确立的国际公认的标准化原则制定的。======意义和用途====== 5.1 该测试方法允许同时测定一个样品消解步骤中的总氮和总磷。 5.2 该测试方法同时测量氧化氨和有机氮（硝酸盐）以及可溶性硝酸盐。通过从未消化样品中减去硝酸盐+亚硝酸盐值，得到TKN: 使用此测试方法时: 其中: TN = 总氮，和 天相投顾 = 总凯氏氮。

1.1 This test method is applicable for the analysis total nitrogen (organic nitrogen + ammonia-N + nitrate-N + nitrite-N) as nitrate and total phosphorus as orthophosphate in unfiltered water samples by alkaline persulfate digestion followed by ion chromatography (IC). 1.2 Total Kjeldahl nitrogen (TKN) is determined by the calculation. To determine TKN subtract the nitrate-N and nitrite-N in a digested sample from a non-digested sample (see Section 4 , Summary of Test Method). 1.3 The limit of detection (LOD), limit of quantitation (LOQ), and reporting range in Table 1 are based on the two-step process for this test method: digestion and analytical step. Because the digestion step requires a sample dilution, the LOD and LOQ are higher than undigested samples. The reporting range, LOD, and LOQ can be modified and perhaps improved depending on several factors (see Section 6 , Interferences). 1.4 The method detection limits (MDL) are shown for reference. The digestion reagent contains background nitrate and results in higher detection limits. MDL will be shown after the interlaboratory study (ILS) is completed. 1.5 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard. 1.6 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use. 1.7 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee. ====== Significance And Use ====== 5.1 This test method allows the simultaneous determination of total nitrogen and total phosphorous from one sample digestion step. 5.2 This test method measures oxidized ammonia and organic nitrogen (as nitrate) and soluble nitrate simultaneously. By subtracting the nitrate + nitrite value from a non-digested sample gives a TKN: When using this test method: where: TN = total nitrogen, and TKN = total Kjeldahl nitrogen.