Can I obtain sodium azide-free formulations?

Yes. Purified antibodies can be formulated without azide for use in conjugation and functional studies, as they can be stored frozen to minimize the risk of microbial contamination. Or conjugates can be formulated at high concentrations with low amounts of sodium azide. This protects the conjugates from microbial contamination during repeated use, and the azide is diluted out in routine applications—which enables conjugate use with live cells and in cell-sorting studies.