Spectrographic Analysis

Optical Emission Spectrometry (OES) is the reference technique for elemental analysis of solid metallic samples and meets the analysis needs of the metals industry - from production control to R&D, incoming material inspection to scrap sorting. OES is able to perform rapid simultaneous analysis of up to sixty elements. Typical applications involve determination of the metallurgical content of iron and steel, aluminum, copper, nickel, zinc, lead and many other metals and alloys.

Optical Emission Spectrometers (OES) is the leading method for analysis of trace metals to determine chemical composition. Suitable for a range of industries and applications, it is used in metal foundries, die casters, manufacturing and metal fabricators. Optical emission spectrometers are used for process and quality control as well as can be applied in many applications where understanding the chemical composition of metal samples is required. OES can cover the complete range of analysis of chemical element concentrations including trace analysis for pure metals as well as alloys. OES is able to function from below the visible spectrum and into the ultraviolet spectrum ( from 130 nanometers to approximately 800 nanometers).

How the OES Analyzer Works

OES analyzers are composed of several components, the first of which is an electrical source that excites atomic particles within the metallic samples in order so that they display a light emission signature. The samples are heated to high-temperatures within the spectrometer though the use of an electrical high voltage source. The resulting electrical discharge travels through the sample, heating and vaporizing the surface material of the sample. At the atomic level, when the discharge interacts with an atom, it will eject some of the electrons from the atom’s outer shell. These outer-shell electrons have a lesser bond to the nucleus as they are further away, and as such, require less energy to be ‘ejected’. In ejecting these electrons, the atom becomes unstable, and in order to restore stability, the atom attracts higher orbit electrons to fill the gaps. The energy released as the electrons move between the two energy levels results in a characteristic light emission. Each element emits a unique configuration of spectral lines that correspond to the electron transitions.


Depending on the element being measured, and degree of accuracy required, the OES analyzer can generate two types of electrical discharges - arc discharge or spark discharges. 

The light in the form of plasma passes into the spectrometers optical system. The light is then separated into element specific wavelengths and a detector measures the intensity of each wavelength.

Finally, a computer processes the data in accordance with predefined calibrations that show specific elemental concentrations.