Simplifying Rare Earth Compound Analysis through HPLC Separation and Direct Detection

Rare earth elements (REEs) are essential to modern technologies, from renewable energy and electronics to defense applications, due to their unique magnetic, catalytic, and electronic properties. However, their chemical similarity makes efficient separation and quantitation a major challenge. We investigated high-performance liquid chromatography (HPLC) as a faster and more practical alternative to conventional solvent extraction and ion-exchange methods. A newly developed stationary phase was employed for REE separations. On this platform, we compared conventional UV–Vis detection with a new vacuum ultraviolet (VUV) detector, both of which enabled direct measurement of REEs without post-column derivatization or dye addition, the most common approach in HPLC separations of REEs. While UV–Vis detection was limited in both sensitivity and the number of REEs observable, VUV-LC expanded the number of detectable REEs and significantly lowered detection limits, all while using a simple mobile phase of water and α-hydroxyisobutyric acid (HIBA). This combination of a new stationary phase with advanced detection provides a straightforward, selective, and sensitive approach for REE analysis.