Electron Probe Microanalysis
EPMA (Electron Probe Microanalysis) combines high-resolution imaging with quantitative elemental composition analysis using a focused electron beam.
O que é EPMA
How EPMA Delivers Quantitative Elemental Composition at the Micron Scale
EPMA (Electron Probe Microanalysis) is an analytical technique that focuses a high-energy electron beam onto a microscopic spot on a sample and measures the characteristic X-rays emitted using wavelength-dispersive spectrometers (WDS) to determine the elemental composition at that point with high precision and accuracy. Unlike EDS-based elemental mapping on an SEM, EPMA's WDS detectors give it superior spectral resolution and lower detection limits, typically down to around 100 parts per million, making it capable of true quantitative, standards-based analysis of major, minor and trace elements in a solid at micron-scale spatial resolution. It is widely used for mineral, metal alloy and inclusion analysis where accurate elemental quantification, not just imaging, is the goal.
What sets us apart
We don't hand over a spectrum. We hand over the interpretation.
Any lab can return peaks and numbers. Our report reads the data. Three differences define what we deliver — illustrated below with a real, anonymized case.
Multiple techniques, one integrated report
We don't hand back five loose reports. We cross-reference every technique's results into a single reading — each signal checked against the others — to reach an answer, not a pile of data.
- Contamination investigation — identifying and tracing the source of a foreign species.
- Performance degradation — explaining why a batch behaves outside expectations.
- New supplier validation — proving equivalence before switching.
3 LDPE batches · 4 techniques converge, NMR reveals the difference
In semicrystalline polymer systems, thermomechanical processing variables influence chain conformational dynamics¹. Solid-state NMR resolves chemical environments at the nanometer scale², sensitive to changes not detectable by XRD or FTIR³.
Technical justification anchored in the literature
Every technique choice and every inference in the report is backed by peer-reviewed literature — with citations in the text. The conclusion isn't loose opinion: it's a traceable argument, defensible in an audit and in front of the client.
- Numbered citations linking claim to source
- Official standards and methods referenced per analyte
- Auditable reasoning end to end
Conclusion and expert opinion
The report closes with a clear position, signed by the Principal Investigator: what the data shows, what can't yet be claimed, and the next step. It includes an honest caveat on the limits of inference — what separates a technical opinion from a guess.
- Explicit technical position, not just results
- Inference limits declared honestly
- Next-step recommendation signed by the P.I.
Four techniques confirmed equivalence; only the solid-state NMR revealed the subtle conformational change not distinguishable by conventional QC — a molecular signature consistent with the atypical filtration behavior.
Without the industrial line's parameters, no direct causal correlation can be established — a complementary step is recommended for elucidation.
Aplicações de mercado
Onde a EPMA entrega resultados
Market Applications
FAQ
Frequently Asked Questions about Electron Probe Microanalysis (EPMA)
What is Electron Probe Microanalysis (EPMA) and how does it differ from SEM-EDS?
- EPMA is a quantitative elemental microanalysis technique that uses a focused electron beam, like SEM, but relies primarily on wavelength-dispersive spectrometers (WDS) instead of, or alongside, energy-dispersive detectors. WDS separates X-ray wavelengths with much higher spectral resolution than EDS, giving more accurate quantification and lower detection limits, particularly for light elements and elements present at low, trace-level concentrations.
How accurate is EPMA for quantitative elemental analysis compared to EDS?
- Because WDS spectrometers have narrower peak widths and less spectral overlap than EDS detectors, EPMA typically achieves better quantitative accuracy and can resolve elements whose X-ray peaks would overlap and be misidentified or misquantified on an EDS system — making it the standard choice when precise, defensible elemental concentrations are required rather than a qualitative estimate.
What sample preparation does EPMA require?
- EPMA generally requires a flat, polished, and electrically conductive (or conductively coated) sample surface, similar to SEM, since accurate quantification depends on a well-defined, planar analysis point. Sample geometry and surface finish are confirmed before analysis to ensure quantitative results are reliable.
Can EPMA analyze specific points, lines, or full elemental maps?
- Yes — EPMA supports point analysis for precise quantification at a single location, line scans across a feature such as a coating or interface, and full compositional mapping across a region, allowing elemental distribution to be visualized as well as quantified.
What kinds of materials questions is EPMA best suited to answer?
- EPMA is particularly well suited to questions requiring precise, quantitative elemental composition at a specific microscopic location — such as confirming trace-element content, characterizing compositional gradients across an interface or coating, or verifying stoichiometry — where EDS's faster but lower-precision results are not sufficient.
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