Spectrometry is a fundamental analytical technique in both research and industry, but it often generates confusion, especially when it comes to mass spectrometry and optical spectrometry. These are two widely used methods, yet they rely on very different physical principles.
In addition, there are other forms of spectrometry — such as atomic spectrometry, nuclear spectrometry, and X-ray spectrometry — each with radically different applications. This article clarifies the differences, comparing mass and optical spectrometry, and ends with a focus on optical emission spectrometry (OES), a field in which GNR is internationally recognized.
What is mass spectrometry and how does it work?
Mass spectrometry (MS) is a technique that measures the mass-to-charge ratio (m/z) of ions produced from a substance. The sample is ionized, and the generated particles are accelerated in an electric or magnetic field. Depending on their mass and charge, they follow different trajectories and reach the detector at different times.
This process produces a unique “fingerprint” of the analyzed substance.
Main applications of mass spectrometry – with practical examples:
- Identification of complex chemical compounds: e.g., detection of pesticide residues in agricultural products.
- Structural analysis of biological molecules: such as protein characterization in biomedical research.
- Proteomics and metabolomics: advanced studies to identify biomarkers of neurodegenerative diseases.
- Environmental and pharmaceutical analysis: monitoring micro-pollutants in water or ensuring drug purity.
Common variants: MALDI-TOF, ESI, ICP-MS, GC-MS, LC-MS.
What is optical spectrometry and how does it work?
Optical spectrometry is based on the interaction between light and matter. Each substance absorbs, transmits, or emits light radiation in a characteristic way, creating a spectral profile that makes it possible to identify and quantify it.
Main optical spectrometry techniques:
- UV-Vis: measures absorption of ultraviolet and visible light.
- IR (infrared): identifies functional groups through IR absorption.
- Raman: analyzes inelastic light scattering to characterize materials and molecules.
- OES (Optical Emission Spectrometry): measures the light emitted by atoms excited in a high-energy source.
Who uses optical spectrometry?
This technology is widely adopted by different types of customers, including:
- Foundries and steelworks, for alloy composition control;
- Automotive and aerospace companies, requiring certified high-performance materials;
- Independent laboratories and universities, for research and advanced testing;
- Energy industries, analyzing materials for nuclear and renewable applications.
Learn more about Optical Emission Spectrometry
Principles and features
Optical emission spectrometry (OES) is today the reference technique for elemental analysis of metals. The sample is introduced into a high-energy source (ICP plasma, arc, or spark), where atoms are excited and emit light at characteristic wavelengths.
By analyzing these emissions, the spectrometer can determine the sample’s elemental composition quickly and accurately.
Evolution of OES
Invented in the early 20th century for steel analysis, OES has evolved dramatically. From the first bulky arc-discharge instruments with limited precision, it has advanced to modern systems equipped with high-resolution optics, advanced software, and compact designs. Today, OES delivers multi-element analyses in just a few seconds, with highly reliable results even in demanding industrial conditions.
Main advantages of optical emission spectrometry:
- rapid, multi-element analysis;
- wide concentration range, from trace levels to high percentages;
- robustness and reliability in heavy-duty industrial environments;
- possibility of integration into production lines for real-time control.
Main applications
Optical spectrometry is a cross-cutting technology, with applications in several sectors:
Metals
- Chemical analysis of metal alloys.
- Production control in foundries, the metalworking industry, and the mechanical industry.
- Positive Material Identification (PMI).
- Quality control of ferrous and non-ferrous metals (e.g., iron alloys, steel, aluminum, copper, nickel, titanium, zinc, tin, magnesium, lead, etc.).
Chemical and petrochemical industry
- Monitoring chemical composition in chemical or petrochemical processes.
Materials science
- Development and characterization of alloys, study of materials in the laboratory.
- Multi-matrix analysis, assessment of purity, detection of impurities.
Learn more about Application in Metal Industry
GNR solutions
GNR is an international leader with more than 40 years of experience in developing optical emission spectrometers. Its solutions stand out for accuracy, speed, and reliability, supporting foundries, steelworks, mechanical companies, and laboratories worldwide.
Key models in GNR’s product line:
- S3 Minilab 300 – compact and versatile, ideal for rapid analysis.
- S7 Metal Lab – designed for high-performance multi-element analysis.
- S6 Sirius 500 – next-generation spectrometer ensuring maximum precision and stability.
👉 Discover GNR Optical Emission Spectrometers
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GNR among the global leaders
The optical emission spectrometry market features major international players such as Thermo Fisher Scientific, Bruker, Spectro (AMETEK), and Hitachi High-Tech. Within this competitive landscape, GNR distinguishes itself as a European excellence, globally recognized for the quality of its instruments and its ability to deliver tailored solutions for metallurgy and materials analysis.
FAQ
Mass spectrometry (MS) measures the mass-to-charge ratio of the ions produced from a sample, allowing highly precise analysis even of complex organic compounds. It is widely used in the biomedical, pharmaceutical, and environmental fields.
Optical emission spectrometry (OES), on the other hand, excites the atoms in a metallic sample using an electric discharge: each element emits a characteristic light that is detected by the spectrometer. It is the most commonly used technique for analyzing metals and alloys (steel, aluminum, copper, titanium, etc.), especially for industrial quality control.
Metallurgical and mechanical industry: quality control in foundries and steelworks, Positive Material Identification (PMI), testing of steels and light alloys.
Materials science: development and characterization of new alloys, research, and laboratory testing.
Chemical and petrochemical industry: monitoring processes and contaminants.
Environmental and clinical analysis: detection of metallic traces in fluids (oils, lubricants, coolants).
On-site analysis: with portable instruments, alloy identification can be carried out directly in production or in warehouses.
The sample (usually metallic) is excited with an electric discharge in a spark or arc. The excited atoms and ions emit characteristic light radiation, which passes through an optical system (diffraction grating and detector). The resulting spectrum shows the presence and concentration of the elements.
A mass spectrometer fragments and ionizes the molecules of the sample. The resulting ions are separated according to their mass-to-charge ratio (m/z) inside an analyzer (e.g., quadrupole, time-of-flight, ion trap). A detector records the signal intensity, generating a mass spectrum that identifies and quantifies the species present.
OES spectrometers are high-tech instruments sold by specialized manufacturers such as GNR Analytical Instruments Group. They can be purchased directly from the company or through its international distributor network.
The price varies greatly depending on the model. As a guideline, an optical emission spectrometer can cost from tens of thousands to several hundred thousand euros, depending on the configuration, number of optical channels, and required performance.
