1.1 本试验方法描述了甲烷（C）上用作燃料的氢气中总碳氢化合物（THC）的测量程序 1. )基础。a C上THC的测定 1. basis是一种分析技术，其中假设所有碳氢化合物与甲烷（CH）具有相同的响应 4. ). 可以实现从0.1体积分数（ppm（v），µmol/mol）到1000 ppm（v）浓度的灵敏度。可以使用适当的稀释技术分析较高浓度。如果已完成潜在干扰的评估，则该测试方法可适用于需要分析微量成分的其他气体样品。 1.2 本试验方法是一种基于火焰离子化检测器（基于氢火焰离子化检测器）的碳氢化合物分析方法，无需使用分离柱。因此，该方法不提供单个碳氢化合物的形态。 制造了多种仪器，可用于该方法。 1.2.1 该方法提供了THC“as CH”的测量 4. ，“因为所有碳氢化合物的定量与CH相同 4. 响应，这是唯一用于校准的物种。氢火焰离子化对碳原子的响应幅度取决于该原子在分子中的化学环境。该方法提供THC结果，就好像所有碳原子都来自脂肪族、芳香族、烯烃或乙炔化合物，其中这些原子引起的检测器响应大约与分子中存在的碳原子数有关。其他类型的分子，包括含氧或氯原子的分子，反应不同，通常比相应的脂肪族碳氢化合物低得多。因此，其他方法（试验方法 D7653 , D7892 ，或等效物）来确定由该方法确定的THC响应的准确成分。 1.3 正确处理含有空气、氮气、氢气或氦气的压缩气瓶需要使用气体调节器，以防止任何仪表组件过压 1.4 单位- 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。 1.5 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。 1.6 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====== 5.1 质子交换膜燃料电池（PEM-FC）等工作温度较低的燃料电池需要高纯度的氢才能实现最大的材料性能和使用寿命。THCs（以CH计）浓度为0.1 ppm（v）的分析 4. )如SAE J2719或法规中所规定，氢气是确保原料气纯度足以满足燃料电池系统需要的必要条件。 5.2 使用高精度质量流量控制器的动态稀释技术可用于THC含量超过仪器线性范围上限的测试样品，无需使用更高水平的校准标准重新校准仪器。可使用高纯度等级的氢（99.999%，只要其含有<0.1 ppm（v）THC）对样品进行稀释，以通过对结果应用适当的稀释因子获得THC含量的结果。 THC浓度大于1000的样品 可以测定ppm（v），但可能会降低精度，并应通过稀释法进行分析。 5.3 尽管本试验方法中的技术不适用于除氢以外的气体，但可适用于需要测定THC含量的其他非碳氢化合物气体样品。这可以通过使用零气体和标定气体来实现，标定气体由与实际样品相同的背景气体组成。例如，对于氮的THC测定，必须使用高纯度等级的氮（99.999%和<0.1 ppm（v）THC）测定仪器零点，并且必须使用CH的认证标准进行仪器校准 4. 在适当的氮气范围内。这将纠正背景气体引起的任何干扰。

1.1 This test method describes a procedure for total hydrocarbons (THC’s) measurement in hydrogen intended as a fuel on a methane (C 1 ) basis. The determination of THC on a C 1 basis is an analytical technique where all the hydrocarbons are assumed to have the same response as methane (CH 4 ). Sensitivity from 0.1 parts per million by volume (ppm(v), µmol/mol) up to 1000 ppm(v) concentration is achievable. Higher concentrations can be analyzed using appropriate dilution techniques. This test method can be applied to other gaseous samples requiring analysis of trace constituents provided an assessment of potential interferences has been accomplished. 1.2 This test method is a Flame Ionization Detector-based (FID-based) hydrocarbon analysis method without the use of separation columns. Therefore, this method does not provide speciation of individual hydrocarbons. Several varieties of instruments are manufactured and can be used for this method. 1.2.1 This method provides a measure of THC “as CH 4 ,” because all hydrocarbon species are quantified the same as CH 4 response, which is the sole species used for calibration. Magnitude of the FID response to an atom of carbon is dependent on the chemical environment of this atom in the molecule. This method provides the THC result as if all carbon atoms are from aliphatic, aromatic, olefinic, or acetylenic compounds, where the detector response caused by these atoms is approximately relative to the number of carbon atoms present in the molecule. Other types of molecules, including those containing oxygen or chlorine atoms, will respond differently and usually much lower than the corresponding aliphatic hydrocarbon. Therefore, other methods (Test Methods D7653 , D7892 , or equivalent) must be utilized to determine the exact constituents of the THC response determined by this method. 1.3 The proper handling of compressed gas cylinders containing air, nitrogen, hydrogen, or helium requires the use of gas regulators to preclude over-pressurization of any instrument component 1.4 Units— The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard. 1.5 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. 1.6 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 Low operating temperature fuel cells such as proton exchange membrane fuel cells (PEM-FC) require high purity hydrogen for maximum material performance and lifetime. Analysis to 0.1 part per million (ppm(v)) concentration of THCs (measured as CH 4 ) in hydrogen is necessary for ensuring a feed gas of sufficient purity to satisfy fuel cell system needs as defined in SAE J2719 or as specified in regulatory codes. 5.2 Dynamic dilution techniques using highly accurate mass flow controllers can be used with test samples that have THC content exceeding the upper limit of the instrument’s linear range, without the need to recalibrate the instrument using higher levels of calibration standards. The sample can be diluted with a high purity grade of hydrogen (99.999 %, so long as it contains < 0.1 ppm(v) THCs) to achieve a result of the THC content by applying the appropriate dilution factor to the result. Samples that contain THC concentrations greater than 1000 ppm(v) may be determined, although results will likey be achieved with reduced precision and should be analyzed by the dilution method. 5.3 Although not intended for application to gases other than hydrogen, techniques within this test method can be applied to other non-hydrocarbon gas samples requiring THC content determination. This can be achieved by using a zero gas and a calibration gas that consist of the same background gas as the actual sample. As an example, for the THC determination of nitrogen, the instrument zero point must be determined with a high purity grade of nitrogen (99.999 % and < 0.1 ppm(v) THCs) and the instrument calibration must be done with a certified standard of CH 4 in nitrogen in the appropriate range. This will correct for any interferences caused by the background gas.