Simple methods to quantify radiochemical impurities existing in glass microspheres were tested. A system of two solvent mobile phases (acetone and 0.9% NaCl) were used with Whatman no. 3 paper strips as the stationary phase. Paper chromatography was used to identify radiochemical impurities in the radioactive microspheres. These impurities were found to be <0.01% for Azer spheres in saline and acetone solution. The results confirmed that glass microspheres prepared using the new procedures are convenient for radiotherapy purposes.