The radiochemical purity (RCP) determination of radiopharmaceuticals is routinely done with radio-thin layer chromatography (r-TLC). These methods are usually transposed and adjusted from the summary product characteristics without any analytical validation. The r-TLC method is simple but manually-performed steps could lead to RCP misinterpretation. To increase the sensitivity, radio ultra-high performance liquid chromatography (r-UHPLC) can be used. In this study, an r-UHPLC method had been validated and compared to the r-TLC method. Hydrolyzed-reduced technetium had also been studied.