XRF for Hexavalent Chromium Detection
Hexavalent chromium, or Cr(VI), is one of the most toxic substances in the RoHS restricted list, and it presents a detection challenge that sets it apart from every other restricted metal.
Understanding what XRF can and cannot do with chromium is essential for anyone building a compliant RoHS testing program.
XRF measures elemental composition. It detects the presence of chromium as an element (total chromium) but it cannot distinguish between the oxidation states of chromium.
Chromium exists in multiple ionic forms, and the RoHS restriction targets specifically Cr(VI), the hexavalent form. Trivalent chromium, Cr(III), is not restricted and is present in many legitimate surface treatments, stainless steel alloys, and industrial coatings.
This means XRF chromium detection is a screening step, not a definitive determination. If XRF finds total chromium above the 0.1% RoHS threshold, that result tells you chromium is present at a concentration that warrants investigation — not that the chromium present is necessarily hexavalent and therefore non-compliant.
The practical value is significant. XRF screens rapidly across all component types and flags elevated chromium concentrations in seconds.
Those flagged samples then proceed to confirmatory testing, typically a colorimetric spot test or laboratory analysis, that specifically determines whether the chromium is in the hexavalent state.
Most chromium in electronics is trivalent. Stainless steel components, chromate conversion coatings applied in compliant Cr(III) processes, and certain decorative finishes all contain chromium that XRF detects and that confirmatory testing clears. The subset of samples where Cr(VI) is actually present — certain older conversion coatings, some specialty platings, legacy surface treatments — gets identified through the XRF-first, confirmatory-second workflow.
Without XRF, you're either sending every component to the lab or testing nothing at all.
With XRF, you're testing everything quickly and sending only flagged samples for the confirmatory step that answers the hexavalent question definitively.
Screen for total chromium fast, and know exactly which samples need confirmatory Cr(VI) testing.
Shop handheld RoHS XRF analyzers at Alloy Geek
More RoHS XRF Resources
There are a lot of ways to save money and time with XRF analysis, especially when it comes to RoHS and other legal compliances. Learn more about the uses and benefits of XRF analysis for your business from an XRF professional.
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