1.1 These test methods are applicable to the determination of microquantities of uranium in water in the concentration range from 0.005 to 50 mg/L.

1.2 The uranium fluorescence is quenched by many cations and some anions in the sample; it is enhanced by a few cations. If interfering ions are present, a direct fluorometric measurement is not suitable, and an extraction method must be used to provide accurate results. The test methods and their concentration ranges are as follows:

Concentration Range, mg/L Sections Test Method A---Direct Fluorometric 0.005 to 2 7 to 15 Test Method B---Extraction 0.04 to 50 16 to 24

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 and health practices and determine the applicability of regulatory limitations prior to use. For specific hazards, see Note 1.