ASTM D3868-15

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 origin of the water, determine if it is a possible pollutant, or if it is related to a potential source of a valuable mineral. For example, in geochemical studies some correlation data indicate that fluoride is an indirect indicator of the presence of lithium.

1.1 This test method2 covers the determination of soluble fluoride ions in brackish water, seawater and brines by use of a fluoride selective electrode.

1.2 Samples containing from 1.0 to 25 mg/L can be analyzed by this test method.

1.3 The values stated in SI units are to be 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 and health practices and determine the applicability of regulatory limitations prior to use.