This standard specifies a method for the determination of potassium content in lithium by flame atomic absorption spectroscopy (AAS), suitable for the determination of potassium content between 0.0005% and 0.04%. Method Absorbance of potassium is determined at 766.5 nm using an air-acetylene flame by dissolving the sample in a nitric acid medium. The standard describes in detail the preparation of reagents, Sample Handling and measurement procedures to ensure the accuracy and conformity of the results, providing a scientific basis for the detection of potassium content in lithium products.