Hughes E E
ISA Trans. 1975;14(4):281-91.
The National Bureau of Standards is engaged in a continuing program involving gaseous Standard Reference Materials for air pollution measurements. Preparation of such materials requires definition of the stability, homogeneity, and accuracy of the samples. This information is obtained by long term studies of the gas systems, by development of absolute methods of analysis, and by analysis of large numbers of samples prepared in bulk. The results of studies, extending over several years, of low concentration of carbon monoxide in nitrogen and nitric oxide in nitrogen are reported. Over one thousand samples of these materials have been analyzed and the stability with time and the within-batch homogeneity have been characterized. Accuracy is achieved by use of gravimetric standards and with dynamic dilution systems. Accuracy attainable by either method is described. The use of permeation tubes of sulfur dioxide and nitrogen dioxide is necessary in some situations because of the reactivity of the gases. Data covering the stability and accuracy of these devices has been collected over a period of several years.
美国国家标准局正在开展一项持续项目，涉及用于空气污染测量的气态标准参考物质。制备此类物质需要确定样品的稳定性、均匀性和准确性。这些信息是通过对气体系统进行长期研究、开发绝对分析方法以及对大量批量制备的样品进行分析获得的。报告了对氮气中低浓度一氧化碳和氮气中一氧化氮进行的长达数年的研究结果。已对这些物质的一千多个样品进行了分析，并表征了其随时间的稳定性和批次内均匀性。通过使用重量标准和动态稀释系统实现准确性。描述了两种方法可达到的准确性。由于这些气体具有反应性，在某些情况下需要使用二氧化硫和二氧化氮渗透管。在数年时间里收集了有关这些装置的稳定性和准确性的数据。
