ASTM International Standard Test Method for Low-Level Dissolved Oxygen in Water ASTM D5543-21

1.1 This test method covers the rapid determination of low-level (<100 µg/L) dissolved oxygen in thermal-cycle steam condensate, deaerated boiler feedwater, boiler water, and deaerated deionized water. Color comparators allow the estimation of concentrations ranging from 0 to 100 µg/L (ppb) oxygen. 1.2 This test method may be applicable to electronic-grade, pharmaceutical-grade , and other high-purity waters, although these were not addressed in the collaborative study. 1.3 It is the user's responsibility to ensure the validity of this test method for waters of untested matrices. 1.4 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.