Monochlorobimane (mBBr) is a fluorescent dye with a λex value of 380 nm and a λem value of 470 nm.Monochlorobimane can be used to measure glutathione (GSH) in cells.

A common technique to measure Glutathione (GSH) in cultured cells is to add Monochlorobimane to the culture medium where it readily enters cells to form a fluorescent GSH-monochlorobimane adduct that can be measured fluorometrically. The Monochlorobimane approach gives comparable results to the HPLC technique. Monochlorobimane concentration can be lowered to 25 mM and still accurately measure homogenate GSH content.[1]