Potassium

Test Method Technical Information

TECHNICAL SPECIFICATION

Tests For: Potassium in Natural and Treated Waters
Tests Range: : 0–12 mg/L
Reagent Chemistry Used: Tetraphenylboron
Method Detection Limit*: 0.3 mg/L
Limit of Quantification**: 0.8 mg/L

*The Method Detection Limit (MDL) is defined as the minimum measured concentration of a substance that can be reported with 99% confidence to be different from the method blank results.

**The Limit of Quantification (LOQ) is the smallest quantity that can be detected with reasonable certainty for a given analytical procedure.

Testing for Potassium

Potassium is an abundant natural element. However, in freshwater potassium levels are normally low. Higher levels can be observed in brackish waters. The guide level prescribed for drinking water supplies under the EEC Regulations is 10 mg/L.

Reagent Chemistry

The Palintest Potassium test is based on a single tablet reagent containing sodium tetraphenylboron. Potassium salts react with sodium tetraphenyl-boron to form an insoluble white complex. At the potassium levels encountered in the test, this is observed as a turbidity in the test sample. The degree of turbidity is proportional to the potassium concentration and is measured using a Palintest Photometer.

EPA, Definition and Procedure for the Determination of the Method Detection Limit, Revision 2, Dec 2016.
IUPAC. Compendium of Chemical Terminology, 2nd ed. (the “Gold Book”).