UV Cleavable Biotin-PEG2-Azide is PEG derivative containing a biotin group and an azide group. The azide group can react with either alkyne moiety in Cu(I)-catalyzed Click Chemistry reaction or DBCO moiety in copper-free Click Chemistry reaction to form a stable triazole linkage. The hydrophilic PEG spacer increases solubility in aqueous media of the molecules conjugated to the biotin compound. Captured target can be released under mild photolysis conditions (365 nm) and results in a significant decrease of background signal due to non-specifically bound proteins.