Inductively coupled plasma optical emission spectroscopy (ICP-OES) is the technique of choice for many different applications, including those in the environmental, metallurgical, geological, petrochemical, pharmaceutical, materials, and food safety arenas. It can be applied to varying sample types such as liquids and solids, and to aqueous and organic samples. Some of these sample types need specific sample preparation techniques or the use of specific accessories.

The advantages of using ICP-OES over other elemental analysis techniques such as inductively coupled plasma mass spectrometry (ICP-MS) or atomic absorption spectrometry (AAS) include its wide linear dynamic range, high matrix tolerance, and the enhanced speed of analysis that can be achieved.


What is ICP-OES?

A plasma will excite the atoms and ions that travel through it. When an atom or ion is excited, its electrons jump from a lower to higher energy level (figure 1). Upon relaxation of these electrons to their initial 'ground' state, energy is emitted in the form of photons. The emitted photons possess wavelengths that are characteristic of their respective elements.

Figure 1. Excitation of an atom by plasma.
Figure 1. Excitation of an atom by a plasma.

One element can have multiple electron excitations and relaxations; therefore, it can have multiple characteristic wavelengths. An example of an emission spectrum for calcium is shown in figure 2.

Visible emission spectrum of calcium

Figure 2. Emission spectrum of calcium in the visible range.
Figure 2. Emission spectrum of calcium in the visible range.

ICP-OES takes advantage of the unique emission spectra of elements to identify and quantify them.

In this section on ICP-OES, you will:

  • Understand the systems and technologies that drive ICP-OES
  • Learn which sample types can be analyzed by ICP-OES and what conditions must be considered during sample preparation and introduction
  • Recognize and correct for factors that interfere with accurate data analysis

ICP-OES information subtopics