Which statement best describes which elements XRF can reliably measure and where challenges exist?

• A. XRF cannot measure most elements near sodium; only heavy elements are detectable.
• B. Most elements from Na and above can be measured; light elements below Na are challenging; detection improves with WDX or special setups.
• C. XRF can measure all elements equally well with standard equipment.
• D. Light elements below Na are easy to measure with standard EDX detectors.

Answer: (B)