ICP (Inductively Coupled Plasma) is used to analyze a sample for cations and sulfate. The soil extract is introduced from the sample cup via a system of tubing. The sample is aspirated as a fine mist through an argon plasma operating at around 1500oC. The heated sample is then measured as it emits wavelengths while it cools down. The wavelength and the intensity are directly proportional to the amount of a certain compound in the extract.
