1.1 本试验方法涵盖了水样中溶解氧（DO）的在线测定，主要在0到500μg/L（ppb）范围内，尽管可以使用更高的范围进行校准。在线仪器用于连续测量通过样品线采集的样品中的溶解氧，必要时通过高温和高压源调节。 1.2 以国际单位制表示的数值应视为标准值。国际单位制后括号中给出的值仅供参考，不被视为标准值。 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、健康和环境实践，并确定监管限制的适用性。 有关具体危害说明，请参阅 6.5 . 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====== 5.1 DO在锅炉/蒸汽循环中可能是一种腐蚀剂或钝化剂，因此被控制在相对于环境和废水处理样品较低的特定浓度。DO浓度超标可能会导致锅炉系统腐蚀，从而导致腐蚀疲劳和腐蚀产物，所有这些都对蒸汽发生器的寿命和有效运行有害。 通过使用在线仪器连续测量去除过程前后的溶解氧浓度，可以监测通过机械或化学方法或两者从锅炉给水中去除溶解氧的效率。DO测量也是检查空气是否泄漏到锅炉水循环中。 5.2 高压锅炉的给水化学指南通常要求特定的给水DO浓度:5 μg/L或更少，用于减少所有挥发性处理[AVT（R）]；5–10 μg/L用于氧化全挥发性处理[AVT（O）]；50–200 微克/升用于充氧治疗 ( 3. ) . 5.3 在微电子生产中，溶解氧在某些制造过程中可能是有害的，例如，在硅片上造成不必要的氧化。

1.1 This test method covers the on-line determination of dissolved oxygen (DO) in water samples primarily in ranges from 0 to 500 μg/L (ppb), although higher ranges may be used for calibration. On-line instrumentation is used for continuous measurements of DO in samples that are brought through sample lines and conditioned from high-temperature and high-pressure sources when necessary. 1.2 The values stated in SI units are to be regarded as standard. The values given in parentheses after SI units are provided for information only and are not considered 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, health, and environmental practices and determine the applicability of regulatory limitations prior to use. For specific hazards statements, see 6.5 . 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 ====== 5.1 DO may be either a corrosive or passivating agent in boiler/steam cycles and is therefore controlled to specific concentrations that are low relative to environmental and wastewater treatment samples. Out-of-specification DO concentrations may cause corrosion in boiler systems, which leads to corrosion fatigue and corrosion products — all detrimental to the life and efficient operation of a steam generator. The efficiency of DO removal from boiler feedwater by mechanical or chemical means, or both, may be monitored by continuously measuring the DO concentration before and after the removal process with on-line instrumentation. DO measurement is also a check for air leakage into the boiler water cycle. 5.2 Feedwater chemistry guidelines for high-pressure boilers generally require specific feedwater DO concentrations: 5 μg/L or less for reducing all volatile treatment [AVT(R)]; 5–10 μg/L for oxidizing all volatile treatment [AVT(O)]; 50–200 μg/L for oxygenated treatment [OT] ( 3 ) . 5.3 In microelectronics production, DO can be detrimental in some manufacturing processes, for example, causing undesirable oxidation on silicon wafers.