Inductively Coupled Plasma – Optical Emission Spectrometry (ICP-OES; also called ICP-Atomic ES) is a technique that makes use of inductively coupled plasma to produce excited atoms (and ions) that emit electromagnetic radiation at wavelengths characteristic of a particular element. Instead of using a flame to get atoms excited, a plasma is used. The plasma is hot ionized argon which is generated by a magnetic field can reach temperatures of 5000-9000 K. At this high temperature almost all elements of the periodic system start to emit light. The intensity of light emission at a specific wavelength is a measure of the element concentration in solution.

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Major components and lay-out of a typical quadrupole ICP-MS instrument

The advantages of ICP-AES are:

• Simultaneous measurement of almost all elements of the periodic system are possible.

• The calibration curve is linear for several decades.

• The detection limit is in general close to 0.1 mg/L.

Disadvantages are:

• Expensive equipment.

• Interferences matrix (e.g. salt level) effects overlap of the spectral lines of the elements and variation in background signal.

ICP-AES/OES is currently very common for measurement of elements in foods.