SC
Specelex

Light Elements

Low atomic number elements (C, O, N, Na, Mg) with poor detectability in standard portable XRF.

Elements below ~atomic number 11 are challenging for portable XRF because their fluorescent X-rays are low energy and easily absorbed.

Carbon in steel — critical for weldability and hardenability — requires OES, not portable XRF. Magnesium and aluminum in alloys are detectable with proper calibration and SDD detectors (Max/Ultra).