An adsorbent used for the recovery of trivalent minor actinides (MA(III); Am and Cm) from high level liquid waste generated from reprocessing of spent nuclear fuel was subjected to micro-particle induced X-ray emission (micro-PIXE) analysis to improve its elution performance. The experimental adsorbent comprised SiO2 particles, a polymer coating, and an N,N,N′,N′-tetraoctyl diglycolamide (TODGA). The particles to be analyzed were subjected to Nd adsorption and an elution operation, but Nd in the adsorbent was found to be uniformly distributed. This might have been caused by individual differences in the amount of impregnated TODGA. The remaining Nd species were not localized to a specific part of the adsorbent after the adsorption operation. Some Nd elements were retained in the adsorbent after elution, probably because of the poor diffusion of the mobile phase inside the adsorbent. An adsorbent having a different microstructure from the first was then evaluated, and rapid elution was observed on new adsorbent along micro-PIXE analysis. •Generally, an adsorbent performance is evaluated with a chemical test.•Micro-PIXE is applied for evaluation of a SiO2-adsorbent performance.•A problem of an adsorbent's performance is solved by micro-PIXE analysis.