1.1 本试验方法涵盖了所有类型皮革（蓝湿革和白湿革）中氮含量的测定。氮含量用于计算皮革、蓝湿革和白湿革的皮物质（蛋白质纤维）含量。 注1: 皮革的原始测试方法基本上是方法的组合 联邦试验方法标准311和方法6441 B5 美国皮革化学家协会。 注2: 如果粘合皮革中含有三聚氰胺，则蛋白质纤维的计算值可能会人为偏高。 1.2 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。 1.3 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和健康实践，并确定监管限制的适用性。 1.4 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 通过本试验方法测定的氮含量通常被认为与皮革样品中存在的皮革物质（蛋白质纤维）的数量有关。系数5.62通常用于根据氮含量计算皮物质。 4.1.1 5.62系数表示许多动物皮分析的平均结果，但不能认为是准确的，因为同一类型的不同皮、不同类型的皮以及最终皮革中保留的皮厚度（与原始皮厚度相比的分割厚度）有所不同。由于这些变化，任何给定皮革的真实系数可能在5之间变化。 44至5.80或约±3 %. 3. 4.2 给定的皮革样品可能含有除皮革物质（蛋白质纤维）以外的含氮物质，皮革物质将通过本试验方法进行分析，例如树脂、染料等，其中含有氮。因此，尽管该试验方法对于测定皮革中的氮含量相当准确，但其用于测定皮革物质可能会产生较大误差。 4.3 从该测定中得出的皮物质值对给定皮革的其他化学测定有很大影响。任何错误，例如 4.1.1 和 4.2 ，将转入这些其他分析计算中。

1.1 This test method covers the determination of the nitrogen content of all types of leather, wet blue and wet white. The nitrogen content is used to calculate the hide substance (protein fiber) content of leather, wet blue and wet white. Note 1: The original test method for leather was essentially a composite of Method 6441 of Federal Test Method Standard No. 311 and Method B5 of the American Leather Chemists Association. Note 2: Melamine, if present in bonded leather, could give an artificially high value for the calculation of protein fiber. 1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard. 1.3 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 and health practices and determine the applicability of regulatory limitations prior to use. 1.4 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 The nitrogen content as determined by this test method is normally considered to be related to the amount of hide substance (protein fiber) present in the leather sample. A factor of 5.62 is normally used to calculate the hide substance from the nitrogen content. 4.1.1 The 5.62 factor represents the average result of many analyses of animal hides, but it cannot be considered to be accurate since it varies somewhat from hide to hide of the same type, from type of hide to type of hide, and also with the thickness of hide retained in the final leather (split thickness as compared to original hide thickness). As a result of these variations, the true factor for any given leather may be expected to vary from 5.44 to 5.80 or about ±3 %. 3 4.2 A given leather sample may contain nitrogenous substances other than hide substance (protein fiber) which will be analyzed for by this test method, such as resins, dyestuffs, etc., that contain nitrogen. Therefore, although this test method is fairly accurate for determining the nitrogen content of leather, its use for determining hide substance may result in large errors. 4.3 The hide substance value derived from this determination has a large bearing on other chemical determinations of a given leather. Any errors, such as those described in 4.1.1 and 4.2 , will be carried over into these other analytical calculations.