Particle Identification and Characterisation by TEM-EDX

BJL Laboratoires examines and characterises particles using transmission electron microscopy (TEM) combined with EDX elemental microanalysis.

This approach enables the direct investigation of particles, dust, deposits, residues and inclusions collected from air, present on sampling media or found in materials, providing information about their morphology and elemental composition.

It can support particulate contamination investigations, non-conformity investigations and efforts to identify the origin of unknown deposits.

What Is TEM-EDX Analysis?

The method combines two complementary techniques:

• Transmission electron microscopy (TEM), which enables particles to be examined at a very small scale and their morphology investigated;
• EDX microanalysis (energy-dispersive X-ray spectroscopy), which provides information about the elemental composition of an observed area or particle.

Combining morphological and elemental information enables a more detailed characterisation of individual contaminant particles than bulk sample analysis alone.

What Can TEM Reveal?

Transmission electron microscopy enables individual particles of very small dimensions to be examined.

Observation can provide information about:

• particle shape;
• morphology;
• dimensions;
• fibrous, compact, angular or irregular appearance;
• the presence of different particle populations;
• morphological differences between samples.

These findings can provide useful clues when investigating the origin of contamination.

What Does EDX Microanalysis Reveal?

Once a particle has been located, EDX microanalysis can be used to obtain its elemental spectrum.

This can reveal the relative presence of different elements within the analysed area.

Depending on the particle, analysis may reveal elements such as:

• silicon;
• aluminium;
• iron;
• calcium;
• magnesium;
• titanium;
• chromium;
• nickel;
• copper;
• zinc;
• other elements detectable by the technique.

The resulting elemental profile can then be assessed in relation to the sample context or compared with potential contamination sources.

Can EDX Precisely Identify a Particle?

EDX primarily provides information about elemental composition.

This information can be highly useful, but it does not always provide a complete chemical identification of a compound.

For example, the presence of several elements in particular proportions may suggest a family of materials, a mineral or metallic origin, or a type of contamination.

Interpretation therefore takes account of:

• the morphology observed by TEM;
• the EDX spectrum;
• the industrial or environmental context;
• materials present on site;
• any comparison samples available.

Identification of Airborne Particles

BJL Laboratoires can investigate particles collected from air when the sampling medium and preparation are compatible with the analysis.

This service may be useful in situations involving:

• dust appearing inside a room;
• airborne contamination in a workshop;
• process-related emissions;
• particles found around equipment;
• comparison of different work areas;
• investigation of a particulate source;
• examination of a sample collected on a filter or another suitable medium.

Morphological and elemental characterisation can help distinguish different particle populations and guide investigation of their origin.

Dust Identification

Dust may contain a mixture of particles from several sources.

TEM-EDX analysis enables individual particles to be investigated, rather than only measuring the average composition of the sample.

This approach can be useful for investigating:

• metallic particles;
• mineral particles;
• particles rich in particular elements;
• different particle groups within the same dust sample;
• a particular population found only in a contaminated sample.

Identification of Particles in Materials

A particle or inclusion in a material may cause a non-conformity, defect or contamination issue.

TEM-EDX analysis can help characterise an isolated particle or a particulate fraction extracted from the material.

Investigations may concern:

• an unusual inclusion;
• a foreign particle;
• dust deposited on a material;
• a manufacturing residue;
• contamination originating from equipment;
• a deposit that appeared during a process.

Analysis of Unknown Deposits

A visible deposit on a component, piece of equipment or surface may originate from various sources.

When it contains particles suitable for analysis, TEM-EDX can provide information to help guide its identification.

Depending on the context, it may be relevant to investigate whether the deposit originates from:

• metallic materials;
• mineral materials;
• wear;
• corrosion;
• a raw material;
• a dusty environment;
• cross-contamination.

Investigation of Metallic Particles

Metallic particles may originate from mechanical wear, equipment, tools, pipework, abrasion or manufacturing operations.

EDX microanalysis provides information about the elements present in a particle.

The combination of elements detected can then be compared with the composition of materials potentially present in the process.

Investigation of Mineral Particles

TEM-EDX can also be used to characterise certain particles of mineral origin.

Combining information about:

• morphology;
• dimensions;
• elemental composition;
• sampling context;

can help guide their classification or indicate their likely origin.

Analysis of Fibres and Elongated Particles

Transmission electron microscopy also enables the examination of elongated particles and fibres.

Investigating their morphology, dimensions and elemental composition can provide useful information for characterisation.

BJL Laboratoires also specialises in asbestos testing in materials and air.

Explore BJL Laboratoires’ asbestos testing services

Investigating the Source of Particulate Contamination

One of the main benefits of TEM-EDX is the ability to compare an unknown particle with different potential sources.

For example, an investigation may compare:

• the contaminant particle;
• raw materials;
• dust present on site;
• residues from equipment;
• wear debris;
• different workshop areas;
• a conforming product and a non-conforming product.

Comparing morphology and elemental composition can help identify similarities or rule out certain hypotheses.

TEM-EDX and Non-Conformity Investigations

Particulate contamination often becomes apparent through:

• a visible deposit;
• a change in appearance;
• an inclusion;
• dust;
• a particle found in a product;
• an unusual feature observed on a surface.

In these situations, TEM-EDX analysis can form part of a broader investigation into the source of the non-conformity.

Explore our analytical non-conformity investigation service

TEM-EDX or Bulk Chemical Analysis?

The two approaches address different analytical requirements.

In some investigations, several of these techniques can provide complementary information.

TEM-EDX and ICP-OES: Two Different Approaches

ICP-OES determines the concentrations of different elements in a sample portion brought into solution.

TEM-EDX examines individual particles and performs microanalysis on a highly localised area.

For example, bulk analysis may indicate that a sample contains iron, while EDX microanalysis may show that a particular particle population is rich in both iron and chromium.

Explore our elemental analysis services using ICP-OES / ICP-AES

TEM-EDX and Organic Analysis

EDX microanalysis is primarily used to obtain elemental information.

When contamination is organic in nature, other techniques may be more suitable.

BJL Laboratoires has capabilities including:

• GC-MS for many volatile or semi-volatile organic compounds;
• LC-MS/MS for targeted analyses compatible with liquid chromatography.

A Combined Analytical Strategy

In some situations, the nature of the contamination is initially unknown.

It may then be appropriate to combine different approaches:

• particle observation and microanalysis by TEM-EDX;
• elemental analysis by ICP-OES;
• testing for organic compounds by GC-MS;
• targeted analysis by LC-MS/MS;
• comparison of several samples.

BJL Laboratoires can assess the most suitable strategy for the problem encountered.

Analytical expertise and consultancy

How Does Particle Identification Work?

1. Understanding the Problem

Before analysis, it is important to understand the circumstances in which the particles appeared.

Useful information includes:

• where the particles were observed;
• when they appeared;
• their visible appearance;
• materials present in the surrounding environment;
• equipment that could generate particles;
• recent process changes.

2. Sample Selection or Preparation

The sample is prepared in a way that is compatible with TEM examination.

Preparation depends on factors including the sampling medium, the nature of the dust and the quantity of material available.

3. TEM Examination

The particles are examined to assess their morphology and select suitable areas for microanalysis.

4. EDX Microanalysis

EDX spectra can be acquired from selected particles to investigate their elemental composition.

5. Interpretation

The morphological and elemental data are then interpreted in the context of the sample.

Comparing a Particle with a Suspected Source

When a potential source has been identified, providing a comparison sample can be particularly useful.

Examples include:

• a suspected raw material;
• a residue from equipment;
• workshop dust;
• a material used in a component;
• a conforming product;
• a sample collected from another area.

Comparison can help establish similarities or rule out certain potential sources.

What Information Should You Send to the Laboratory?

Who Can Benefit from TEM-EDX Particle Analysis?

This service may be useful for:

• industrial businesses;
• quality departments;
• R&D teams;
• laboratories;
• engineering and environmental consultancies;
• technical experts;
• environmental professionals;
• companies dealing with particulate contamination.

Particle Identification Services Across France

BJL Laboratoires is based in Sèvres, in the Hauts-de-Seine department, near Paris.

Where the sample and its packaging are suitable for transport, samples can be sent to the laboratory from anywhere in France.

For a specific particulate contamination investigation, please contact BJL Laboratoires before sending samples to agree on suitable sampling and packaging arrangements.

Accreditation and TEM-EDX Analysis

BJL Laboratoires is a Cofrac-accredited laboratory.

The laboratory’s accredited status must be distinguished from whether a particular analysis falls within its scope of accreditation.

The status of a service depends on factors including:

• the matrix;
• the parameter investigated;
• the method used.

A specific investigation or particle identification service may therefore be performed outside the scope of accreditation. The applicable status is specified according to the service requested.

Frequently Asked Questions about TEM-EDX Particle Identification

Related Services

• Analytical investigation of non-conformities
• Analytical expertise and consultancy
• Custom chemical analysis
• ICP-OES / ICP-AES analysis
• GC-MS analysis
• LC-MS/MS analysis
• Asbestos testing