Qualitative & Quantitative Analysis

Energy dispersive X-ray fluorescence analysis (EDXRF) is a fast, qualitative elemental analysis technique. Typically all elements from sodium (Na) through to uranium (U) can be detected simultaneously, with good quality spectra obtained in minutes, or even seconds. Each element peak occurs at a known fixed position and generally concentrations from 100% down to sub-ppm are detectable with EDXRF. The lower limit depends on the particular instrument’s configuration.

XRF is mostly a quantitative technique – the peak-height for any element is directly related to the concentration of that element within the sampling volume. However, extreme care must be taken because two or more elements can interact with each other, resulting in contamination and thus skewed results. For example, chlorine atoms strongly absorb fluorescent X-Rays from lead – thus, if chlorine is present, the observed lead signal will be much less intense than expected for a particular concentration.

The ability of fluorescent X-rays to penetrate through and escape from the sample itself depends on their energy, which directly relates to which elements are being detected. The lighter elements all have very low energy X-rays (e.g. Na, Mg, Al and Si) and thus it is difficult to detect these even at relatively shallow depths within the sample. Heavier elements (e.g., Cu, Ag, and Au) have higher energy X-rays, which are able to traverse larger distances within the sample.
The sample composition itself is also an important factor- the higher the concentration of the heavier elements which absorb strongly, the lower is the chance of X-rays escaping from deep within the sample.

xrfschematics

Physics of X-ray fluorescence, in a schematic representation

  • Usage

    XRF spectroscopy is widely used for qualitative and quantitative elemental analysis of environmental, archaeological, geological, biological, industrial and other samples.
  • Compared to rival techniques, such as Atomic Absorption Spectroscopy (AAS), Inductively Coupled Plasma Spectroscopy (ICPS) and Neutron Activation Analysis (NAA), XRF has the advantage of being non-destructive, multi-elemental, fast and cost-effective.
  • Furthermore, XRF provides a good, uniform detection level across a large portion of the Periodic Table and is applicable to a wide range of concentrations, from 100% down to a few parts per million (ppm).
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Oxford Labs – FAQ

Which materials is XRF suitable for?
XRF can be used to test a wide range of materials from ceramics to metals and glass. It has various applications in industry, in environmental studies and the verification of antiquities. Read more

How do I get my item analyzed?
We can test on our premises or on site. Contact Oxford Labs for details of the services we offer.
How long does it take?
The process is fast and efficient. We aim to provide documentation and return of your items within two weeks. Read more

What results can I expect?
The chemical composition of the sampled area will be determined. We can offer an opinion as to the historical periods with which these results are consistent based on comparison with our database of known genuine results.
Does the process damage the item?
XRF does not damage the item. It is a safe and non-destructive process. Read more ...

What is the cost?
We offer a comprehensive service at a competitive price. Click here for our scale of charges.

What documentation will you provide?
The analysis will be fully documented and a signed certificate will be provided.