1.1 这些试验方法包括测定水中的氨氮，不包括有机氮。包括以下两种试验方法: 小节 试验方法A-直接硬化 7 – 16 试验方法B-离子选择电极 17 – 24 1.2 试验方法A用于常规测定蒸汽冷凝液和除盐装置废水中的氨。 1.3 试验方法B适用于测定0.5至1000 mg NH范围内的氨氮 3. N/L直接在试剂和出水中。稀释后可以确定更高的浓度。报告的下限基于多操作员精度。参与循环赛的12个实验室中的两个已经获得了下限。 1.4 试验方法A和B均适用于地表水和工业水以及蒸馏后的废水。蒸馏试验方法见 附录X1 过去用于满足氨分析样品预蒸馏的要求。 1.5 以国际单位制表示的数值应视为标准值。本标准不包括其他计量单位。 1.6 本标准并非旨在解决与其使用相关的所有安全问题（如有）。本标准的用户有责任在使用前制定适当的安全、健康和环境实践，并确定监管限制的适用性。 1.7 蒸馏方法现在显示为 附录X1 仅作为非强制性信息提供。自动比色酚法已停止使用。 1.8 本国际标准是根据世界贸易组织技术性贸易壁垒（TBT）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》中确立的国际公认标准化原则制定的。 ====意义和用途====== 4.1 氮是环境中的一种营养素，是维持大多数生物体生长所必需的。它以多种形式存在，如硝酸盐、亚硝酸盐、有机氮（如蛋白质或氨基酸）和氨。 4.2 氨是一种无色气态化合物，具有强烈的独特气味。 它高度溶于水，以与水相关的分子形式存在，并以NH的电离形式存在 4. + . 缔合或电离的程度取决于温度和pH值。它也可能对水生生物有毒。毒性程度取决于物种和解离程度。 4. 氨水可能是含氮化合物厌氧分解的产物，也可能是含氨废水的产物。

1.1 These test methods cover the determination of ammonia nitrogen, exclusive of organic nitrogen, in water. Two test methods are included as follows: Sections Test Method A—Direct Nesslerization 7 – 16 Test Method B—Ion Selective Electrode 17 – 24 1.2 Test Method A is used for the routine determination of ammonia in steam condensates and demineralizer effluents. 1.3 Test Method B is applicable to the determination of ammonia nitrogen in the range from 0.5 to 1000 mg NH 3 N/L directly in reagent and effluent waters. Higher concentrations can be determined following dilution. The reported lower range is based on multiple-operator precision. Lower limits have been obtained by two of the twelve laboratories participating in the round robin. 1.4 Both test methods A and B are applicable to surface and industrial waters and wastewaters following distillation. The test method for distillation given in Appendix X1 has been used in the past to meet requirements for predistillation of samples being analyzed for ammonia. 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 The distillation method now appears as Appendix X1 and is provided as nonmandatory information only. The automated colorimetric phenate method has been discontinued. 1.8 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 ====== 4.1 Nitrogen is a nutrient in the environment and is necessary to sustain growth of most organisms. It exists in several forms such as nitrate, nitrite, organic nitrogen such as proteins or amino acids, and ammonia. 4.2 Ammonia is a colorless, gaseous compound with a sharp distinctive odor. It is highly soluble in water where it exists in a molecular form associated with water and in an ionized form as NH 4 + . The extent of association or ionization is dependent on the temperature and pH. It may also be toxic to aquatic life. The extent of toxicity is dependent upon species and extent of dissociation. 4 Ammonia may occur in water as a product of anaerobic decomposition of nitrogen containing compounds or from waste streams containing ammonia.