FAQ's on XRF Reference Standards

​Associates of our in-house XRF standards laboratory work closely with many customers to support a wide range of X-Ray Fluorescence (XRF) reference material needs. The work includes routine inspection and certification of existing standards, as well as consultation services and manufacturing of new XRF reference standards tailored to specific applications.

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various xrf reference standards

Since Eastern Applied Research specializes in supporting Energy-Dispersive XRF (ED-XRF) technology, much of our work relates to coating thickness reference standards. These include both single-element coatings and alloy coatings like zinc-nickel and electroless nickel where composition is critical. We also support ED-XRF elemental analysis applications, most commonly RoHS testing. In addition, we have seen a growing demand for certified alloy materials designed for use with handheld XRF analyzers.

The end users we support represent a broad range of experience levels, from those new to XRF capabilities to seasoned professionals. Our lab associates help with questions from fundamental concepts to advanced, application-specific challenges – in this post, we have collected a few of the most common questions relating to certified reference materials for XRF analyzers (with answers, of course).

​Contact the XRF Standards Laboratory of Eastern Applied with any questions you may have relating to XRF reference standards.

The Fundamental Questions:

• What is a reference standard that would be used in an XRF?
  • Reference standards are materials with a certified and known elemental composition used to calibrate or verify the performance of XRF Analyzers. We frequently work with standards for coating thickness applications but also various elemental analysis uses.
• What is the purpose of reference standards?
  • To ensure accuracy and precision in measurements by correcting instrument drift, matrix effects, and other variables.
• Do I need reference standards for my XRF?
  • This depends on your use of X-Ray Fluorescence and the analyzer. Even when some units have fundamental parameter (FP) programs, they will still need at least one reference piece.

Calibration and Verification

• How often should I calibrate my XRF analyzer using standards?
  • This depends on usage, regulatory requirements, application, and the make/model of XRF. Routine checks may be daily or weekly. Full recalibration is typically less frequent unless there’s a change in method or environment. This is different from a full certification service performed by an accredited, outside, organization (learn more about XRF certifications).

Choosing the Right Standards

• Can I use the same standards for different materials (i.e. metals vs plastics)?
  • No, standards must match the matrix (composition and physical form) of the sample being analyzed for accurate results.
• How do I choose appropriate reference standards?
  • You can work with application specialists in our in-house standards laboratory to determine the right standards for your needs. You will want to match your sample matrix, make certain your reference materials are within a range of composition or thickness, and are traceable to a certified reference material.

Certification, Lifespan, and Traceability

• How long do reference standards last?
  • If properly stored and handled, most solid standards can last for many years. However, they should be routinely inspected for contamination or degradation. Inspection is especially critical with thickness standards…plated thickness standards can wear, and foil standards can wrinkle or be punctured (read more about plated vs foil XRF standards).
• Do my standards need to be traceable to a national or international body (i.e. NIST)?
  • Yes, for regulated industries or accredited labs, traceability to a standards body like NIST is often required. An accredited service provider, like Eastern Applied Research, will certify your materials with traceability to NIST reference materials.

Punctured XRF Standard, Gold Foil

Practical Use & Troubleshooting

• Why are my results drifting even after using standards?
  • As a first step, make sure you have the right calibration standards in hand and are working in the right calibration file. However, a drifting XRF analyzer is an indication that something is wrong, and you should call the XRF Service Center of Eastern Applied Research. Associates can help troubleshoot environmental conditions (i.e. temperature, humidity changes), if there is a component issue like an older detector tube, or possible issues with your reference standards like contamination or wear.
• Can I create my own in-house reference standard?
  • You can create “working standards,” but they need to be validated against certified standards for reliability.
• Do I need different standards for handheld vs benchtop XRF?
  • The first step is to confirm what the application is and if both analyzers are set up for that. If they are the same, then Handheld XRF analyzers would need larger pieces, but they could be used on a bench-top system. Most pieces manufactured for a bench-top analyzer will, however, not work with a handheld because of size.

This isn’t a full list of questions we hear and may not cover your questions. Please contact our XRF Standards Laboratory to discuss any of your questions or XRF reference material needs.