Standard X-ray fluorescence (XRF) spectrometers are fundamentally unable to detect very light elements with atomic numbers below sodium (such as hydrogen, helium, lithium, beryllium, boron, carbon, nitrogen, oxygen, fluorine, and neon) because their emitted characteristic X-rays are too weak to escape the sample matrix or penetrate detector windows. Furthermore, XRF cannot reveal chemical bonding states, molecular structures, or internal spatial distributions, as it only measures total elemental concentration by mass at the surface level.