Inductively Coupled Plasma Optical Emission Spectroscopy (ICP-OES)

Inductively Coupled Plasma Optical Emission Spectroscopy (ICP-OES)

Inductively Coupled Plasma Optical Emission Spectroscopy (ICP-OES) is a technique that uses high-temperature plasma, to produce free atoms and ions of a vaporized sample, for elemental analysis by Optical Emission Spectroscopy (OES). The plasma generator is an inductively coupled (ICP) type, comprising concentric quartz tubes surrounded by an induction coil. Argon gas is commonly used, being converted to plasma by an intense electromagnetic field produced by the induction coil. Analyte samples are prepared as solutions or colloidal suspensions in liquid and introduced into the plasma in aerosol form, using a nebulizer. At high plasma temperatures, atoms are excited to higher energy levels and upon their return to the ground state, their optical emissions (photons) exhibit characteristic wavelengths, depending on the element. The intensity of emissions depends on the concentration of the excited atoms. These characteristic wavelengths are separated and measured by an optical spectrometer When calibrated against standards, quantitative estimates of elemental compositions can be obtained.

This technique is also referred to as inductively coupled plasma atomic emission spectroscopy (ICP-AES).  ICP-OES is suitable for almost every element, excluding halogens and inert gases, and are especially useful for refractory elements, such as Silicon, Aluminium, Barium, that are difficult to analyze by flame atomic absorption spectroscopy (FAAS).

Common uses of ICP-OES

• Determination of trace metals in food and beverages
• Analysis of major, minor, and trace elements in coal
• Elemental analysis of biomaterials
• Trace element analysis in ceramic materials
• Environmental samples analysis for trace elements
• Motor oil analysis
• Elemental analysis of oilfield waters
• Forensic analysis

Advantages of ICP-OES

• High specificity and multi-element analysis capability
• Sensitive upto parts per billion levels of trace elements
• Atom and ion spectra can be used
• Rapid and economical

 Limitations of  ICP-OES

• Overlap of sensitive spectral lines due to rich spectra
• High background radiation

Industrial Applications of ICP-OES

• Fossil fuels
• Ceramics
• Metallurgical
• Environmental
• Biomaterials
• Food and beverages

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