OES analysis operates by ablating sample material through high-frequency electrical sparks applied between a metallic sample and an electrode. The ablated material is excited in the argon plasma generated by the sparks, emitting light in the VUV-visible range. Each element emits light at characteristic wavelengths, and the intensity of this light is proportional to the element’s concentration in the sample. This emitted light is directed towards the optical system, where a diffraction grating separates the polychromatic light into its monochromatic components. Photons at the wavelengths of interest are typically detected by photo-multiplier tubes (PMTs) and converted into electrical signals, though CCD detectors may also be used to collect the full spectrum or parts of it.

OES is a robust and reliable technology, particularly well-suited for the analysis of metals and alloys. It is the most widely used technique in industries dealing with iron and steel, aluminum, copper, nickel, zinc, lead, tin, cobalt, titanium, magnesium, precious metals, and specialty metals/alloys. OES offers the fastest analysis of all elements with high precision and accuracy. Sample preparation is straightforward, typically involving paper grinding or milling. High throughput is routinely achieved, with over 400 samples processed per day, all at a low cost of ownership.

Advantages of OES

• Speed and Robustness: OES is fast, precise, stable, and reliable.
• Simplicity: Sample preparation is easy.
• Cost-Effective: Low capital investment and operating costs.
• Versatility: Capable of analyzing elements from trace (sub-ppm) to alloy concentration levels.
• Efficiency: Provides rapid quantitative determination of elements in pure metals and alloys in under one minute.
• Specialized Analysis: Excellent for analyzing carbon, nitrogen, oxygen, phosphorus, and sulfur in steel.
• Inclusion Analysis: Ultra-fast analysis of non-metallic inclusions.

Applications of OES

• Primary Metals Production: Fe, Al, Cu, Mg, Ti, Au, and more.
• Foundries
• Metals Processing
• Metals Recycling

Supply chains are becoming more complex and potentially less reliable, while legislation concerning trace elements is increasingly stringent. Consequently, foundries and metals processing companies must meticulously analyze and control the materials entering and exiting their facilities to consistently produce high-quality, profitable products that meet all specifications and legislative requirements. This necessity can be challenging.

Each element must be tested to comply with material specifications. Contemporary specifications often surpass the capabilities of many mid-range OES analyzers. High-end OES analyzers, while offering advanced capabilities, are not viable for the majority of users and may not always meet the demands of high-throughput production environments.