X-ray Fluorescence (XRF)

The technique in brief

In X-ray Fluorescence (XRF) samples are exposed to a beam of X-rays. Some of the energy from this beam is absorbed by the atoms of the sample which themselves may then emit secondary (fluorescence) X-rays (the characteristics of which are unique to each element). An XRF measures the intensity and characteristic energy/wavelength of the secondary X-rays and can provide qualitative and quantitative analysis of the material being tested.

Current instrumentation:

The current XRF at the AAC is a Bruker-AXS S4 Pioneer X-ray Fluorescence Spectrometer. It has a 108 position sample changer and allows elemental analysis on solid (B - U) and (Na - U) for liquid samples. SpectraPlus software is used to operate the spectrometer.

Applications:

XRF is routinely used as a method of qualitative and quantitative chemical analysis of geological, environmental, biological and industrial materials. The technique is applicable to a wide range of elements at concentrations from weight % to parts per million (ppm).

Accurate quantitative analysis requires calibration based on a range of standards that reflect the matrix (sample type) and range of concentrations of elements in the material to be analysed. Semi-quantitative analysis can also be employed whereby X-ray intensities are compared against a library of standards from a range of sample types. Whilst not as accurate as quantitative analysis, it is an excellent method for determining the relative abundance of elements in unknown samples.

Sample requirements

Typically samples need be crushed to a fine powder and then either fused to make a glass disk (for major elements) or pressed into a pellet (for trace element and semi-quantitative analyses).

For further information contact the officer in charge:

Shane Askew or Jen Whan