Inductively coupled plasma mass spectrometry

Inductively coupled plasma mass spectrometry

ICP-MS Instrument
Acronym	ICP-MS
Classification	Mass spectrometry
Analytes	atomic and polyatomic species in plasma, with exceptions; usually interpreted towards concentrations of chemical elements in sample
Manufacturers	Skyray, Agilent, Analytik Jena, Horiba, PerkinElmer, Shimadzu, Spectro, Thermo, GBC Scientific, Nu Instruments
Other techniques
Related	Inductively coupled plasma atomic emission spectroscopy
Hyphenated	Liquid chromatography-inductively coupled plasma mass spectrometry (LC-ICP-MS), Gas chromatography-inductively coupled plasma mass spectrometry (GC-ICP-MS), Laser Ablation Inductively Coupled Mass Spectrometry (LA-ICP-MS)

Inductively coupled plasma mass spectrometry (ICP-MS) is a type of mass spectrometry which is capable of detecting metals and several non-metals at concentrations as low as one part in 10¹⁵ (part per quadrillion, ppq) on non-interfered low-background isotopes. This is achieved by ionizing the sample with inductively coupled plasma and then using a mass spectrometer to separate and quantify those ions.

Compared to atomic absorption spectroscopy, ICP-MS has greater speed, precision, and sensitivity. However, compared with other types of mass spectrometry, such as thermal ionization mass spectrometry (TIMS) and glow discharge mass spectrometry (GD-MS), ICP-MS introduces many interfering species: argon from the plasma, component gases of air that leak through the cone orifices, and contamination from glassware and the cones.

The variety of applications exceeds that of inductively coupled plasma atomic emission spectroscopy and includes isotopic speciation. Due to possible applications in nuclear technologies, ICP-MS hardware is a subject for special exporting regulations.

An inductively coupled plasma is a plasma that is energized (ionized) by inductively heating the gas with an electromagnetic coil, and contains a sufficient concentration of ions and electrons to make the gas electrically conductive. Even a partially ionized gas in which as little as 1% of the particles are ionized can have the characteristics of a plasma (i.e., response to magnetic fields and high electrical conductivity). The plasmas used in spectrochemical analysis are essentially electrically neutral, with each positive charge on an ion balanced by a free electron. In these plasmas the positive ions are almost all singly charged and there are few negative ions, so there are nearly equal amounts of ions and electrons in each unit volume of plasma.