ASTM D7781-23

1.1 This test method is applicable to the determination of nitrate plus nitrite (as nitrogen) in drinking water, surface, saline, wastewater, and ground waters. The applicable range of this test method is from 0.05 to 5 mg/L of nitrogen. The range may be extended upward by dilution of an appropriate aliquot. The 40 CFR Part 136 Method Detection Limit (MDL) is 0.02 mg/L.

1.2 It is the user's responsibility to ensure the validity of this test method for waters of untested matrices. The quality control criteria in Section 17 for method blanks, laboratory control samples, matrix spikes and matrix duplicates must be met.

1.3 The values stated in SI units are regarded as standard. No other units of measurement are included in this standard.

1.4 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.

1.5 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.