Standardless XRF & Fundamental Parameters Explained

Fundamental Parameters (FP) is a physics-based approach used to estimate elemental composition from XRF spectra while correcting for interactions between elements in the sample. It is especially useful when a full matrix-matched empirical calibration is not available.

What Fundamental Parameters Does

FP calculations model the relationship between composition and measured X-ray intensity, including attenuation and absorption/enhancement effects. Training material from San Francisco State University / FDA describes FP as an iterative approach that adjusts element concentrations until the modeled response matches the measured spectrum.

• Uses physics-based correction rather than relying only on a single empirical calibration curve.
• Can be useful for alloys, well-characterized matrices, and samples containing measurable concentrations of the relevant elements.
• Helps account for inter-element matrix effects that influence measured intensity.
• Still depends on correct element identification, sample presentation, and reasonable assumptions about the matrix.

What “Standardless” Does — and Does Not — Mean

“Standardless” does not mean that every result is automatically equivalent to a matrix-specific certified calibration. It means the software can estimate composition without building a dedicated empirical calibration for every sample type. For demanding quantitative work, standards or certified reference materials may still be preferred for verification or matrix-specific calibration.

When FP Is a Good Fit

• Unknown-material screening
• Supplier or lot-to-lot comparison
• Alloy and metal evaluation
• R&D samples where a dedicated calibration does not yet exist
• Broad composition screening before deciding whether another analytical method is needed

See How Accurate Is XRF Analysis? for the factors that determine quantitative performance.

Technical reference: Thermo Fisher — ARL QUANT’X EDXRF application note ↗