Actinidic acid is primarily used in analytical chemistry for the detection and determination of certain metal ions, especially in qualitative inorganic analysis. It acts as a selective precipitating agent for metals such as barium, strontium, and calcium under controlled pH conditions. Due to its ability to form insoluble complexes with specific cations, it is employed in separation procedures to isolate these ions from mixtures. The acid is also utilized in environmental and industrial water testing to assess hardness by targeting multivalent cations. Its application extends to research settings where precise ion manipulation is required, offering a reliable method for purification and identification in complex samples.