XRF glass disks following sample fusion

Keeping ahead through expertise in sample preparation by borate fusion

Good sample preparation is essential for performing high-quality chemical analysis using XRF or ICP and AA. Whichever samples are being assessed – loose or pressed powders, fused beads, bulk solids or liquids – finding the right approach to sample preparation is the first and one of the most important step in achieving accurate and reproducible results.

One of the many benefits of X-ray fluorescence (XRF) spectrometry in comparison to other elemental analytical techniques is that it requires only very simple preparation of samples for analysis. Even so, XRF delivers the most accurate and reliable measurement results when close attention is paid to this vital part of the analytical process:

  • To get the material in the correct form to fit into the instrument
  • To minimize effects such as: particle size effect, mineralogical effect, sample heterogeneity, surface roughness, texture, etc.

Since X-ray fluorescence is a comparative technique, the standards used for calibration must closely match the characteristics of the unknown samples to provide an accurate and precise analysis. Borate Fusion is the only sample preparation technique that allows you to matrix-match the standards and unknowns covering a wide range of materials. It ensures optimal analytical results and has a high cost-saving potential!

What is borate fusion?

Borate fusion is a sample preparation method developed in the mid-50s. It consists of dissolving at high temperatures a fully oxidized sample into a suitable solvent (a glass forming flux). The molten mixture is homogenized and poured into a mold to create a glass disk for XRF analysis. Alternatively, it can be poured into a beaker and dissolved into a dilute acid solution to provide a solution for AA or ICP analysis.

In addition, using the same preparation equipment, it is also possible to prepare solutions for AA or ICP analysis via Peroxide digestion.

Why should I use borate fusion in my laboratory?

Whether you are conducting XRF or ICP and AA analysis, borate fusion is an efficient technique to prepare various types of samples from the most diverse industry segments, including building materials, mining, metals, academia, petrochemicals, animal feed and nanomaterials.

This universal technique has numerous benefits when compared with other sample preparation methods such as pressed pellets or acid digestion.

Borate fusionPressed pellets
Affected by mineralogyNoYes
Affected by particle sizeNoYes
Desirable size of powder (microns)50-100 (easy)5-30 (difficult)
Accuracy≤ 1%≤ 10%
Easy calibration with synthetic standarsYesNo
Application of matrix correctionYesNo
Sample preparation methods compared

Other advantages of sample preparation by borate fusion over other techniques:

  • Requires no handling of concentrated acids or other hazardous chemicals, making it safer than most other digestion techniques.
  • Involves straightforward, easy-to-learn procedures
  • Accommodates a wide range of sample types – liquids, powders and solids
  • Simple, fast and effective
  • Leads to highly accurate and repeatable results
  • Easy to use
  • Cost-effective

Ask an expert

On March 2nd, we will hold the first webinar in a series of Ask an expert webinars. During this webinar we will fully focus on how to prepare your samples for XRF analysis to achieve the best results. Do you need new ways to re-think sample prep challenges, want to sharpen your analytical skills, or simply find out what Malvern Panalytical can offer you? This webinar’s just right.

‘Ask an expert’ is for students, researchers or professors who want to sharpen their analytical method, deepen their knowledge, or may be starting a new research and want to know what can help improve their data. After all, science moves faster when we share what we know. 

We aim to provide basic coverage and tips about sample preparation for XRF and answering common questions. You can send in your questions and/or data prior to the webinar by getting in touch by emailing askanexpert@malvernpanalytical.com or using the #MPexpert hashtag on Twitter. Our in-house expert Jose Eduardo Gardolinski, Sample Preparation Lab Manager, will then handle a selection of the incoming questions during the live webinar. In other words, this is the ultimate way of improving your materials science research!