ASTM D4192-15
Standard Test Method for Potassium in Water by Atomic Absorption Spectrophotometry

Standard No.

ASTM D4192-15

Release Date

2015

Published By

American Society for Testing and Materials (ASTM)

Latest

ASTM D4192-15

Scope

5.1 Potassium occurs in rocks in a form that is not easily solubilized; therefore, the potassium content of natural waters is usually low. Most natural waters contain less than 20 mg/L of potassium, but waters containing several hundred milligrams per litre are occasionally found. Potassium is essential to animal nutrition, but a concentration of 1000 to 2000 mg/L in stock water is regarded as the extreme limit permissible.

1.1 This test method covers the determination of low amounts of potassium in waters2 having low solids content. The applicable range of this test method is 0.20 to 4.0 mg/L when using the 766.5-nm resonance line. The range may be extended upward by dilution of an appropriate aliquot of sample or by using the less-sensitive 404.4-nm resonance line. Many workers have found that this test method is reliable for potassium levels to 0.02 mg/L, but use of this test method at this low level is dependent on the configuration of the aspirator and nebulizer systems available in the atomic absorption spectrophotometer as well as the skill of the analyst. The precision and bias data presented are insufficient to justify use of this test method in the 0.02-mg/L range.

1.2 This test method has been used successfully with spiked reagent water. It is the analyst's responsibility to ensure the validity of this test method to other low dissolved solids matrices.

1.3 The values stated in SI units are to be regarded as standard. The values given in parentheses are mathematical conversions to inch-pound units that are provided for information only and are not considered 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. For a specific precautionary statement, see 8.6.

ASTM D4192-15 Referenced Document

• ASTM D1066 Standard Practice for Sampling Steam
• ASTM D1129 Standard Terminology Relating to Water
• ASTM D1193 Standard Specification for Reagent Water
• ASTM D2777 Standard Practice for Determination of Precision and Bias of Applicable Methods of Committee D-19 on Water
• ASTM D3370 Standard Practices for Sampling Water from Closed Conduits
• ASTM D4841 Standard Practice for Estimation of Holding Time for Water Samples Containing Organic and Inorganic Constituents
• ASTM D5810 Standard Guide for Spiking into Aqueous Samples 
• ASTM D5847 Standard Practice for Writing Quality Control Specifications for Standard Test Methods for Water Analysis

ASTM D4192-15 history

• 2015 ASTM D4192-15 Standard Test Method for Potassium in Water by Atomic Absorption Spectrophotometry
• 2008 ASTM D4192-08 Standard Test Method for Potassium in Water by Atomic Absorption Spectrophotometry
• 2003 ASTM D4192-03 Standard Test Method for Potassium in Water by Atomic Absorption Spectrophotometry
• 1997 ASTM D4192-97 Standard Test Method for Potassium in Water by Atomic Absorption Spectrophotometry