What are the methods used for potassium ion analysis?

There are various methods for potassium ion analysis. 

• The flame photometry technique involves using a flame to vaporize a sample. The sample will then ionize and absorb energy from the flame and emit light of a wavelength as excited as the excited atoms decay to the unexcited ground state. The intensity of emission is proportional to the concentration of the element in the solution. It is a simple, rapid, and reproducible procedure. 
• Ion-selective electrodes are another technique used for potassium ion analysis. These are specialized sensors which include a selective membrane to minimize matrix interference. 
• The Inductively Coupled Plasma Optical Emission Spectroscopy (ICP-OES) method is used to determine how much of certain elements are in a sample. It uses the principle that ions and atoms can absorb energy to transport electrons from the ground state to the excited state. The source of the energy is heat from an argon plasma which functions at 10,000 kelvin. 
• Atomic absorption spectroscopy is a method that detects samples in either liquid or solid samples through determining wavelengths of electromagnetic radiation from a light source. Individual ions will absorb wavelengths differently and their absorbances are measured against standards.