Abstract:

According to Appendix A of GB/T 37244—2018 Fuel specification for proton exchange membrane fuel cell vehicles—Hydrogen, the hydrogen chloride content in hydrogen samples for fuel cell vehicles is tested by ion chromatography, and the uncertainty in the testing process is evaluated. The results show that the standard uncertainty components of standard curve establishment, sample absorption process and repeatability test are 0.033 1, 0.016 1 and 0.001 1, respectively. The main source of uncertainty is standard curve fitting, and the uncertainty introduced by this process accounts for about 50%. When the fiducial probability is 95% and the coverage factor(k) is 2, the uncertainty of the result is reduced from 0.24 μmol/mol to 0.18 μmol/mol by measuring the standard solution twice in parallel and re-fitting the standard curve, and the measurement result of hydrogen chloride content is(3.25±0.18)μmol/mol. Therefore, the uncertainty of test results can be reduced and the accuracy of test results can be improved by measuring the concentration points of standard solution in parallel for many times.

Key words: fuel cell vehicle, hydrogen, hydrogen chloride, uncertainty, repeatability, standard curve, sample absorption, extension,  

摘要：

按照GB/T 37244—2018《质子交换膜燃料电池汽车用燃料氢气》附录A中氢气中总卤化物含量的测定方法，采用离子色谱法对燃料电池汽车用氢气样品中的氯化氢含量进行测试，并对测试过程中的不确定度进行评估。结果表明，标准曲线建立、样品吸收过程和重复性测试的标准不确定度分量分别为0.033 1,0.016 1和0.001 1,不确定度的主要来源为标准曲线拟合，该过程引入的不确定度占约50%。取置信概率为95%,包含因子k=2,通过对标准溶液进行两次平行测定重新拟合标准曲线，将结果不确定度由0.24μmol/mol降低至0.18μmol/mol,氯化氢的摩尔分数最终测定结果为(3.25±0.18)μmol/mol。因此，在检测中，可以通过多次平行测定标准溶液等方式降低测试结果的不确定度，提高检测结果的准确性。

关键词: 燃料电池车, 氢气, 氯化氢, 不确定度, 重复性, 标准曲线, 样品吸收, 扩展