5.1 Identification of a brackish water, seawater, or brine is determined by comparison of the concentrations of their dissolved constituents. The results are used to evaluate the water as a possible pollutant, or as a commercial source of a valuable constituent such as lithium.

1.1 This test method covers the determination of soluble lithium, potassium, and sodium ions in brackish water, seawater, and brines by atomic absorption spectrophotometry.2

1.2 Samples containing from 0.1 to 70 000 mg/L of lithium, potassium, and sodium may be analyzed by this test method.

1.3 This test method has been used successfully with artificial brine samples. 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. The values given in parentheses are mathematical conversion to inch-pound units that are provided for information only and are not considered 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.