ICPOES consists of an inductively coupled plasma (ICP) interfaced to an optical emission spectrophotometer (OES) and is used for simultaneous multi-analyte determination of ~78 elements on the periodic table. The ICP is one of several types of plasma discharges used in analytical atomic spectroscopy created using inert gases, typically argon. The plasma is created by ionization of plasma gas in an electromagnetic field produced within the confines of a work coil using a radio-frequency signal. Collisions between gas atoms and charged particles in the plasma result in a temperature of ~8000K inside the plasma discharge. The plasma discharge is a “hard” ion source, effectively decomposing all sample components into their constituent atoms then ionizing these atoms. As the ions produced move into the cooler region of the plasma they return to the ground state by absorbing electrons, simultaneously emitting light at the characteristic wavelengths of the element. The emitted light is separated into a spectrum and the intensity of each emission line measured at the detector. Detectors include charge coupled devices (CCD), charge injection devices (CID), and diode arrays. CCDs and CIDs are most common as they have wavelength coverage from the ultraviolet (UV) to infrared (IR) region of the spectrum, and can capture full spectral images allowing simultaneous quantitation of all detected emission. The typical working range is low part per billion (ppb) to percent composition (%).